RFID reader module: MFRC522
So, hello to all viewers and welcome back to Gettobyte Platform. In This blog you are going to know about RFID Reader MFRC522, which is designed by NXP Semiconductors. Objective would be to interface this module with Host MCU’s like of NXP Semiconductors, STMicroelectronics or other vendors MCU’s. Will make the driver to interface the RFID Reader with any MCU, not unlike just with Arduino and Arduino IDE environment. To make the driver of RFID reader at first, we need to dig into its datasheet, to understand its various sub parts. And that’s all about this blog is gotten going to be, to make the datasheet understand in easy way-out.
Table of Contents
Next & Previous Blog
RFID Technology
RFID modules is a wireless sensing technology which is used to track/identify/monitor the objects.
MFRC522 RFID Reader/PCD
MFRC522 is a highly integrated reader/writer IC for contactless communication at 13.56 MHz. These reader supports the ISO 14443 A protocol for communicating with RFID Tags. They are used to detect the MIFRAME RFID tags.
MFRC522 has internal RF transceiver, which provides a robust and efficient implementation for demodulating and decoding signals from MIFRAME compatible cards using ISO 14443 A protocol. The digital module of MFRC522 manages the complete ISO/IEC 14443 A framing and error detection (parity and CRC) functionality.
MFRC522 supports 3 tags of MIFRAME family, that are MF1xxS20, MF1xxS70 and MF1S50 products.
MFRC522 features
MFRC522 though quite old RFID reader and in today’s time many new advance RFID readers have come up. But so as to get started with this technology as a hobbyist/student/DIY project, it is perfect module to lay your hands on this Technology.
- MFRC522 has highly integrated analog circuitry to demodulate and decode responses when RFID tags are brought in close proximity of these devices.
- RFID readers are connected with some host MCU, where the processing of data which is received via RFID tags happens according to the application. MFRC522 can connect with host MCU, using SPI, Serial UART and I2C -bus interface.
- It supports ISO 14443 A protocol and can be used with MIFRAME family of RFID tags. And in MIFRAME family it supports only MF1xxS20, MF1xxS70 and MF1xxS50 products.
- It has internal CRC-coprocessor.
- Internal FIFO buffer which can handle 64 bytes of sending and receiving.
- It uses the Crypto-1 cipher for authenticating.
- It supports Internal oscillator for connection to 27.12 MHz quartz crytsal.
- It is low power device, need 2.5 V to 3.3 V power supply.
- It also has flexible interrupt modes when some RFID tags are detected and trigering events too. In addition to flexible interrupt, it has programmabe I/O pins and timer.
- It can perform Internal self-test too.
MFRC522 Functional description
MFRC522 Host Interfaces
MFRC522 can be connected to Host MCU using 3 serial protocols: UART, I2C or SPI.
MFRC522 checks the current host interface type.
automatically after performing a power-on or hard reset. The MFRC522 IC identifies the host
interface by sensing the logic levels on the below pins after the reset phase. 
The MFRC522 is equipped with a series of registers that allow the Host MCU to access its functional description blocks. To ensure the proper functioning of the MFRC522, the Host MCU must initialize and configure these functional blocks by sending the corresponding register addresses.
Each register is essentially an address byte that is transmitted from the Host MCU. Depending on the function described in the register section, read/write operations are performed on the corresponding address byte.
It is crucial to properly initialize and configure these functional blocks to ensure the optimal performance of the MFRC522. By understanding the purpose of each register and its corresponding function, the Host MCU can effectively communicate with the MFRC522 and achieve the desired results.
–> MFRC522_write_register()
–> MFRC522_Read_register()
MFRC522 Interrupts
MFRC522 can trigger the interrupts, when certain events occur. There are 8 events as shown in below table when interrupt can be triggered.
When above event occurs, IRQ pin is used to interrupt the host. IRQ pin signal is asserted and host MCU can use its interrupt handling capabilities (basically NVIC if we are talking about ARM based MCU) on what to do when corresponding interrupt has occurred.
- Status1Reg Register IRq bit is used to indicate if any interrupt source has been triggerered.
- Which interrupt has been triggered is indicated by ComIrqReg and DivIrqReg Register. 
- Which interrupts to be configured and behavior of IRQ pin is configured by ComIEReg and DivIEReg Register.
MFRC522 Time Unit
There is a Timer unit in MFRC522, that is used for multiple purposes. Timer unit is essential for maintaing the configuring the clock and analog interfaces. Also timer unit can be used for following features:
- Timeout counter
- Watchdog counter
- Stopwatch
- Programmable one shot
- Periodical trigger
Timer has an input clock of 13.56 MHz derived from the 27.12 MHz quartz crystal oscillator. The timer consists of 2 stages: prescaler and counter.
- The prescaler(TPrescaler) is a 12-bit counter. That can be configured using TModeReg register’s TPrescaler_Hi[3:0] and TPrescalerReg register’s TPrescaler[7:0] bits.
- The Reload value for the counter is defined by 16 bits between 0 & 65535 in the TReloadReg register.
- The current value of the timer is indicated in the TCounterVAlReg Register.
MFRC522 FIFO
FIFO overview
The MFRC522 contains an internal FIFO buffer of 64 bytes, which is equivalent to 8 x 64 bits. This buffer is utilized for both input and output data streams. The host MCU has the capability to perform both Read and Write operations on this FIFO. The host MCU sends commands to PCD for communication with PICC. these commands are specified in ISO14443 A standard, which is then inputted into the FIFO. When the PICC responds to these commands, the response is also stored in the FIFO. The host MCU can then read the FIFO to obtain the response from the PICC.
The FIFO buffer is a crucial component in the communication process between the host MCU and the PICC. It allows for efficient data transfer and ensures that all responses are stored in a centralized location. The ability to perform both Read and Write operations on the FIFO provides flexibility and control to the host MCU. By utilizing the FIFO buffer, the communication process is streamlined and optimized for maximum efficiency.
About FIFO registers
FIFO buffer input and output data bus is connected to the FIFODataReg register. Writing to this register stores one byte in the FIFO buffer and increments the internal FIFO buffer write pointer. Reading from this register shows the FIFO buffer contents stored in FIFO read pointer and decrements the FIFO buffer read pointer.
Only one FIFO buffer has been implemented which can be used for input and output. The microcontroller must
ensure that there is not any unintentional FIFO buffer accesses.
The FIFOLevelReg is utilized to determine the number of bytes stored in the FIFO. This register is particularly useful in checking the number of bytes received in the FIFO buffer when the PICC sends a response to the PCD command. By using the FIFOLevelReg, you can easily keep track of the amount of data stored in the FIFO, which is essential in ensuring the smooth operation of your system.
One can also get the status of FIFO buffer using status and error registers.
- FIFO buffer almost full warning can be got to know from Status1Reg register’s HiAlert bit.
- FIFO buffer almost empty warning can be got to know from Status1Reg register’s LoAlert bit.
- FIFO buffer overflow warning, using ErrorReg register’s BufferOvfl bit.
MFRC522 CRC
MFRC522 has a Cyclic Rebudency Check (CRC) coprocessor to check the integrity of the data when data from PICC is received or when data is wriiten to PICC.
- CRC has preset value 0000h, 6363h, A671h or FFFFh. We can configure the preset values using ModeReg CRCPreset[1:0].
- CRC polynomial for the 16-bit CRC is fixed to x^16 + x^12 + x^5 + 1.
- CRCResultReg register indicates the result of the CRC calculation.
- CRC algorithm which is used is according to ISO/IEC 14443 A and ITU-T.
To perform the CRC calculation refer its state machine in below section.
MFRC522 Command Set
MFRC522 operation is determined by certain commands. According to these commands, correspondingly MFRC522 would be performing some action.
So, it’s like at first, we will configure the FIFO, CRC, Interrupts and timer unit. After that Host MCU will instruct the commands to MFRC522 in order to tell what it has to do. Host MCU will write the command code to the CommandReg Register.
Main commands that would be used are Idle, Transceive, CalcCRC and Transmit commands. Transceive command is the one which has to be sent from Host MCU to MFRC522 to send the FIFO buffer data to the antenna, which is further propagated to the RFID readers. And according to the data which we have written in FIFO RFID readers would act and give response.
Each command that needs a data bit stream (or data byte stream) as an input immediately processes any data in the FIFO buffer. An exception to this rule is the
Transceive command. Using this command, transmission is started with the BitFramingReg register’s StartSend bit.
MFRC522 Block Diagram
Above is the simplified block diagram of MFRC522 module. MFRC522 has an internal memory, power supply, interrupt pins, FIFO buffer, Antenna and analog interface, digital module for communicating with Host MCU.
Analog Interface handles the modulation and demodulation of the analog signals. FIFO Buffer ensures fast and convenient data transfer.
Register bank are the set of registers through which MFRC522 would be configured and initialized to use. Parameters like Clock, Interrupts, status of errors while communicating with RFID readers, CRC calculation, FIFO configuration and etc need to be configured before using the MFRC522.
How the MFRC522 Internal system works?
Host MCU will send PCD Commands to MFRC522, according to which it will perform some operations. MCU will send these commands by writing into one of the registers of PCD.( For MFRC522 CommandReg is register)
Operations like:
- Activation of CRC Coprocessor
- Transmission of data from FIFO buffer of MFRC522 and activation of receiver circuits to get the response from PICC
- transfer of data from FIFO to an internal buffer
- soft reset and authentication-based operations
Further MFRC522 will emit the commands for communicating with PICC, here referred to as PICC Commands, according to which operation with PICC takes place, like scanning of PICC, selecting the PICC, reading and writing the data on PICC. MFRC522 emits these commands via electromagnetic induction and electric coupling. ( That is the main working principle behind the RFID technology)
Host MCU to PCD
Host MCU will send the commands to PCD, according to which PCD will perform the operations like activation of FIFO buffer or CRC coprocessor, and transmission of data from FIFO. We will name these commands as MFRC522 Commands sets. Host MCU will send those commands to PCD (here MFRC522) by writing into the CommandReg Register using low level Host Interface write API.
- Idle Command: Places the MFRC522 in Idle mode.
- Mem Command: Transfers the 25 bytes from the FIFO Buffer to the internal buffer. This command is used when, we want to read the data from PICC( As described in ISO-14443-4 doc), as PICC response is always recorded in PCD FIFO.
- Generate RandomID: generates a 10-byte random ID number.
- CalcCRC: Activates the CRC coprocessor or performs a self test.
- Transmit: transmit data from the FIFO buffer
- NoCmdChange: no command change, can be used to modify the CommandRef register bits without affecting the command
- Receive: activates the receiver circuits
- Transceive: Transmit data from the FIFO buffer to antenna and automatically activates the receiver after transmission.
- MFAuthent: performs the MIFARE standard authentication as a reader
- SoftReset: This command performs a reset of the device. The configuration data of the internal buffer remains unchanged. All registers are set to the reset values. This command automatically terminates when finished.
PCD to PICC
Further there are also command set which PCD have to emit to communicate with PICC and enter the PICC into some state machine.
PICC States:
- Power-off State: In the POWER-OFF state, the PICC is not powered by a PCD operating field
- Idle State: In the IDLE state, the PICC is powered. It listens for commands and shall recognize REQA and WUPA commands.
- Ready State: Cascade levels are handled inside this state to get the complete UID. PICC enters the ACTIVE state when it is selected with its complete UID.
- Active State: PICC complies with ISO-14443-4 to accept protocol activation commands (RATS)
- HALT State: In this state PICC only responds to WUPA command.
- Protocol State: PICC behaves according to 1s014443-4 specifications.
We will name these commands as PICC commands. Host MCU will write these PICC command into the PCD FIFO (refer the MFRC522 FIFO section on how to write the data on FIFO). PCD would transmit the FIFO data when it enters the Transceiver state machine (refer above topic).
PCD would transmit these commands via the electromagnetic induction and communicates with PICC via electronic coupling. PCD’s have RF transceivers through which it emits the electromagnetic waves with commands sets encoded in them. PICC have antenna and small circuitry, which gets energized via electromagnetic waves emitted by PCD and then further both PCD and PICC get coupled together to have 2 way wireless communication. How PCD would send commands to PICC and in return how PICC would respond, that is done according to IS014443 protocol. ISO14443 specifies all the frame formats,PICC command and their format , modulation schemes for RFID technology. 
PICC Frame formats:
- Short Frame:
- Standard Frames
PICC Command Set:
- REQA/WUPA Command: This command is send by PCD to scan the valid and IS014443 compatible PICC’s. This command is in short frame format. Host MCU will write this command into the PCD FIFO, from where this command is transmitted and emitted wirelessly. Response to this command is with ATQA. PICC are in Idle state when listening to this command and after successfully transmitting the ATQA response they enter into Ready State. These commands consist of 7 bits, as specified below:
- ANTICOLLISION/SELECT Command: PICC are in ready state when listening to this command and after this command they enter into ACTIVE STATE. This Command is used to get the UID of the scanned PICC and further select the corresponding PICC for Reading and writing data from it. For the MF1S503 PICC’s UID is of 4 bytes, for that only 1 cascade level is needed.
These commands need to be configured and then these bytes are written into The PCD FIFO for transmission and emission of signal to PICC wirelessly. This Command consists of:
- Select code SEL(1byte): Specify the cascade level.
- No of valid bits NVB (1 byte): specify number of bytes that would be transmitted by PCD to PICC (including SEL, NVB and below point)
- 0 to 40 data bits of UID according to value of NVB.
ANTICOLLISION Command consist of:
- Select Code: Cascade level 1= 0x93
- No of valid bits NVB = 0x20
Response to ANTICOLLISION Command is with the UID of the Scanned PICC(0xEA, 0x24, 0x77, 0x15) and its CRC(0xAC).
- SELECT Command consists of:
- Select code: Cascade level 1 = 0x93
- No of valid bits NVB – 0x70
- 0 to 40 data bits of UID that has been received in ANTICOLLISION Command( 0xEA, 0x24, 0x77, 0x15)
- CRCA(1 byte) : CRC of SELECT Command would be calculated by PCD and then it would be sent to PICC. And When PICC receives the SELECT Command it will check this CRCA and then will send the ACK.(0xAC)
Response to SELECT Command is with the Select Acknowledge:
MFRC522 Hardware and Pinout
MFRC522 IC has 32 pins in total and it comes in SOT617-1 package.
Pin description can be found from the datasheet of MFRC522. To use the MFRC522 IC its module is widely available and quite inexpensive. Can be brought from Robu at cost of 150 rupees. With the module an RFID tag and a key fob tag of MIFRAME Classic 1KB comes in.
In MFRC522 module, IC has 8 pins exposed out for connection and connecting to host MCU.
- The module has 4 pins exposed out for connecting it to host MCU using either SPI, I2C or UART. By default, reader can communicate with a microcontroller over a 4-pin SPI with a maximum data rate of 10 Mbps. It also supports I2C and UART protocols. As told in MFRC522 functional description part, MFRC522 checks the host interface type automatically depending on the signals on it’s control pins.
- MFRC522 module has 1 interrupt pin also exposed out, which can be used to trigger interrupts to alert the microcontroller when a RFID tag is in the vicinity.
- And remaining 3 pins are power supply pins and a reset pin. Reset pin is used for power down mode and reset signal. Module requires the power supply of 3.3 V, that is provided via VCC and GND pins.
Other vendor RFID readers
STMicroelectronics
Texas Instruments
Infenion technologies
Sensor & Modules to explore
Technologies to Explore
Other Blog to Explore
S32K1xx Automotive MCU course( Intermediate)
DAC PDB MTB(Micro Trace Buffer) Miscellaneous Control Module(MCM) System Integration Module Crossbar Switch Lite Memory Protection Unit Peripheral Bridge Trigger MUX Control External watchdog Monitor Error Injection Module Error reporting module CRC Watchdog timer DAC Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo. PDB Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo. MTB(Micro Trace Buffer) Tab Content Miscellaneous Control Module(MCM) Tab Content System Integration Module Tab Content Crossbar Switch Lite Tab Content Memory Protection Unit Tab Content Peripheral Bridge Tab Content Trigger MUX Control Tab Content External watchdog Monitor Tab Content Error Injection Module Tab Content Error reporting module Tab Content CRC Tab Content Watchdog timer Tab Content CAN FlexIO LIN CAN Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo. FlexIO Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo. LIN Tab Content Author: Kunal Gupta
What is E/E Architecture in Automotive
Overview In a car at a time more than 100 small or large electronic subsystems are present. Most of these subsystems are connected directly or indirectly in one way or another. Now virtualize that this is a car and it has an Airbag control system which is controlled according to the vehicle motion monitoring system. If Vehicle motion experiences a sudden break or impact, the Airbag control system will be turned on. For understanding, let’s say the Airbag control system is Node A and the Vehicle motion monitoring system is Node B. Node B is situated at the front of the car and Node A is distributed on every seat of the vehicle. So Node B and Node A are connected directly to each other. But let’s say now there is one more Node C. Node C is a car Backlight. Now Node C and Node B are connected in a way if the vehicle motion experiences a sudden break then the car’s backlight has to be turned on immediately. As Car’s backlight is at the back, Node C is at the back of Car and Node B is at the front of the car, so we have to connect Node C and Node B also. Now wiring to connect to Node B and Node C would be required more to take it from front to back. Whereas if we place Node B at the center of the car, then the connection of Node A and Node C would be comparatively easy to do and fewer wires would be used. You can see the electronic subsystems used in cars are distributed across the vehicle. The arrangement of these electronic sub-systems, their architecture of placement and connection is what going to be the topic of today’s video. How the car electronic subsystems are connected, is what is gonna be the topic of today’s video. Surrounded by large-scale technological requirements (ADAS, connected vehicles, Software Defined Cars, Vehicle to Vehicle, Electrification, etc.) established OEMs and semiconductor companies are innovating and differentiating via the architecture designs for the arrangement of these electronic subsystems in a car. In the last video/blog, we learned about different electronic/electrical sub-systems that are there in the car. Now we are going to dwell on architecture on how the different electronic/electrical sub-systems are arranged in an automotive vehicle. What is E/E Architecture E/E architecture is the terminology for arrangmant of elecrical/electromcnis used in car. E/E Architecture organizes and integrates a vehicle’s electrical and electronic systems, including hardware and software components, to ensure they all work together seamlessly. E/E Architecture involves the design of the arrangement of electrical and electronic systems that control various functions of a vehicle, such as a powertrain, safety systems, infotainment, climate control and etc. E/E architecture is also termed as vehicle architecture. The E/E architecture is an arrangement of different components of a vehicle, all combine to make up the vehicle architecture. These components are : 1) electronics hardware 2) network communications 3) software applications, and 4) wiring involved to connect different electric/electrical sub-parts of the system. Why is E/E Architecture or Vehicle Architecture needed? Okay so now we have understand what is E/E architecture, now lets dwell into why do we need E/E architecture concept in automotive vehicle;s. Integration of computing technology into every aspect of the car has transformed how automotive OEMs approach design, engineering and manufacturing of automotive electrical sub-systems. Concurrently, the introduction of sensors into the vehicle architecture further accelerated the need for greater computing power to process and analyze the resulting data. The advancement toward connected cars led to a divergence in how carmakers approached the communication architecture of a vehicle’s electronics. The result of this innovation and integration is a tremendously complex system of electronic control units (ECUs), sensors, actuators, and wiring to connect it all together. The size and complexity of these architectures create new challenges for automotive OEMs and their suppliers. In this environment, the importance of the underlying E/E architecture is paramount. The new generation of automotive consumers expect constant internet connectivity, a fully customizable driving or riding experience, as well as personalized entertainment and functionalities. Simultaneously, consumers expect to feel safe and secure, while enjoying the latest, modern features on-demand, in real-time and over-the-air as they download different applications and services from vehicle “app-stores”. In fact, the vehicle is no longer the focal point in the consumer’s mind, rather it is the mobility service or mobility experience that it provides. Different aspects of E/E architecture are sensors, microcontrollers/processors, networking protocols, wiring and power distribution. All aspects of the E/E architecture occupy a larger role in enabling core vehicle functionalities. As a result, all aspects have grown in sophistication to meet these increased demands. Microcontrollers/processors have become more powerful to process the data coming in from larger sensor arrays using increasingly capable software. Meanwhile, vehicle networks have to manage the communications in this intricate system of sensors and controllers. The result of these innovations and integration is a tremendously complex system of electronic control units (ECUs), sensors, actuators, and wiring to connect it all together. The size and complexity of these electrical/electronic subsystems create new challenges for automotive OEMs and their suppliers. These challenges will only become more intense as companies continue to advance vehicle technologies, particularly in the automated driving space. In this environment, the importance of the underlying E/E architecture is paramount. Surrounded by large-scale technological change, have forced established OEMs to innovate and differentiate via the E/E architecture for automotive sub-systems. This means creating architectures that are scalable across vehicle platforms, flexible to future technologies, and reliable over extended lives in the field. Types of E/E Architecture There are 3 types of E/E architecture in automotive: Flat architecture Domain Architecture Zonal Architecture Up until the past decade, vehicle electronics used a flat architecture where embedded ECUs operated together in a limited way. Flat Architecture: In the context of automotive electronics, a flat architecture refers to a system where embedded electronic control units (ECUs) act
RECTIFIER CIRCUIT
Why do we need a rectifier Circuit? Whenever DC power is needed that time, we need to convert an AC Power to DC Power and that process is known as Rectification. A simple PN junction diode acts as a rectifier. The forward biassing and reverse biassing conditions of the diode makes the rectification. Types of Rectifier circuits There are two main types of rectifier circuits, depending upon their output. They are Half-wave Rectifier Full-wave Rectifier A Half-wave rectifier circuit rectifies only positive half cycles of the input supply whereas a Full-wave rectifier circuit rectifies both positive and negative half cycles of the input supply. Half-wave Rectifier Disadvantages of a half-wave rectifier Power is delivered only during the one-half cycle of the input alternating voltage. Ripple factor is high, therefore required to give steady dc output. They only allow a half cycle through per sine wave, and the other half cycle is wasted. This leads to power loss. Full-wave rectifier FWR has two types as follows: Centre tapped full wave rectifier Bridge full-wave Rectifier 1) Centre tapped full wave rectifier Advantages of a center-tapped full-wave rectifier: The ripple factor is much less than that of a half-wave rectifier. DC load current values are twice those of a half-wave rectifier. The rectification efficiency of the full-wave rectifier is double that of a half-wave rectifier. Disadvantages of center-tapped full-wave rectifier Location of center-tapping is difficult. The dc output voltage is small. The PIV of the diodes should be high. 2) Full-wave bridge rectifier Advantages of bridge rectifier: The need for the center-tapped transformer is eliminated. It can be used in application floating output terminals; no output terminal is grounded. The transformer utilization factor, in the case of the bridge rectifier, is higher than that of a center tap rectifier. Disadvantages of Bridge Rectifiers over center tap rectifiers. It requires four diodes for operation, thus, circuit components requirements in the case of the bridge rectifier are more than that of center tap rectifiers. The voltage drop across diodes increases four times that of a center tap full-wave rectifier. Types of Components and Its Symbol used in circuit Schematic of bridge rectifier PCB Layout of bridge rectifier Track Width – 1.00 mm Bill of material During the PCB assembly process, a BOM provides information about the components under a single roof such as their quantity, reference designators, footprints, etc. Designers will save lots of time and effort during PCB design by preparing a bill of materials with all the updated parts list. Every line of the bill of materials (BOM) includes the product code, part name, part number, part revision, description, quantity, unit of measure, size, length, weight, and specifications or features of the product. Go to fabrication bar in Easyeda online tool Download BOM Gerber File Each artwork layer, copper circuitry, power, or ground must have a corresponding Gerber file to create the required pattern. The outermost layers, referenced as “top” and “bottom,” component and solder or by layer count will also have a conforming layer for solder mask and silkscreen to be applied. Summary In this second blog, we have created a schematic of bridge rectifier and pcb layout also and learnt about bill of material and Gerber file. Apart from that we have seen that type of rectifier and understood which one is suitable for industry. Reference https://www.powerelectronicsnews.com/power-supply-design-notes-rectifier-circuits/ https://www.tutorialspoint.com/electronic_circuits/electronic_circuits_full_wave_rectifier.htm https://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/rectifier-circuits/ Author: Kunal Gupta
Introduction on embedded c
Embedded C is an extremely popular programming language when we talk about electronic devices. If you wanna go for robotics it would be a good start for you. In our day-to-day life, we use mobile, laptops, and fridges every electronic device we use is made up of using embedded C. Now without wasting any time let\’s dive a bit deep into it by looking into a very basic example Blinking LED using Embedded C. Blinking Led is a hello world for embedded C which means this is the first basic code that takes us into the world of embedded C. #define F_CPU 16000000UL#include <avr/io.h>#include <util/delay.h>int main(void){DDRB|= (0B00100000);while (1){PORTB=0B00100000;_delay_ms(1000);PORTB=0B11011111;_delay_ms(1000);}return(0);} Let’s understand our code from top to bottom. #define F_CPU 16000000UL Let’s break it into 3 parts #define F_CPU Here we are defining the clock speed of the processor. 16000000 Here we are setting the clock speed at 16Mhz as our atmega328p’s default value is 1Mhz hence 16Mhz will make it 16 times slower. UL Here we are doing nothing but declaring the data type of the clock speed. We used unsigned long because clock speed cant is negative. #include <avr/io.h> Whenever we want to use libraries of some function from some other source or even we wanna use our own code we use #include. #include <avr/io.h> includes a header file that contains code for using pins, ports, etc. for the Avr microcontroller. #include <util/delay.h> This library is used to put delays in our code. int main(void) The main function is when the AVR starts executing code. While(1) While loops execute the code inside it until the condition inside the parentheses remains true. We all know in C 1 refers to true and 0 refers to false. Here the code inside the while loop will run again and again because 1 can never be false. return(0); If we don\’t write return(0) at the end of the code we will get an error for sure. This happens because our operating system needs confirmation that the code we ran is running properly. This is more of a line of confirmation. You must be wondering what these words DDRB or PORTB are? Well, these are called hardware registers which are extremely important to understand so let\’s get to know what they are and what they do? Hardware Registers In our Atmega series of Avr, we have mainly 3 hardware registers. DDRx PORTx PINx Here x is referred to the bank. We have three of’em B, C, D.Every bank contains 8 pins. Depending on which bank’s pin you are using we chose the bank. DDRx[Data-Direction registers] DDRx configures the pins as output or input. As we are using an 8-bit microcontroller. The default value of the DDR is 0 which means whenever we give power it is not giving any output. If we want to set it for the output we need to set the bit we want to use for sending the output as 1. Output = 1Input = 0DDRB = 0b00000000 DDRB = 0b00100000 Here 0b is telling us that we are writing the number in binary. We all know 0 refers to the ‘off’ and 1 refers to the ‘on’. Hence the above example is telling us at first all pins were off later on we set pin 5 as 1 for giving output. If you are familiar with Arduino Ide then you can relate DDR with pinMode. PORTx[Port x data registers] After setting the DDRx bits to the 1(output), The port registers the voltage as HIGH or LOW. When we say the voltage is Low it means the voltage is 0V and if we say voltage is HIGH we consider the voltage as 5V. HIGH = 1LOW = 0PORTB = 0b00000000 PORTB = 0b00100000 If we take the example of our code we have seen above we are setting pb5 as output. In the picture you can see above PB5 is connected with pin 13 of Arduino. Now you can see we are turning we Led on which is connected with pin 13 which is connected with PB5 on Atmega 328p. If you are familiar with Arduino Ide then you can relate PORTx with digitalWrite. PINx[port c input data pin address] The pin register addresses are used when we want to read the digital voltage values for each pin we set as input in DDRX. You can relate this pin with digitalRead from Arduino IDE. I believe now it\’s clear what we did in the above example. In the next blog, we will see how we can write a function and use it for calling. So that we can reduce our writing. Author: Kunal Gupta
HOW TO START WITH PCB DESIGNING?
Hello Friends, I’m Taral Mehta. I\’m an Electronics Engineer, This is the first blog of the series to discuss and learn the basics of PCB designing. In this blog, we will discuss, Introduction of PCB and its designing techniques. As well as we will discuss various software that are used for designing the PCB. Table of Contents Starting with Basics of ELectricity Before going to start with PCB designing, we will understand the basic components required: Current – Current is the rate of flow of electric charge. at all points in a series circuit, the current has the same value. If a circuit has a branch, the current flowing into the junction must equal the current flowing out of it. Voltage – Voltage is also known as potential difference.In a circuit loop, the sum of the voltages across the power supplies is always equal to the sum of the voltages across the rest of the components. RESISTOR – Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms CAPACITOR – A capacitor is an electronic component that stores and releases electricity in a circuit. It also passes alternating current without passing direct current. Introduction to PCB (Printed Circuit Board) As an Engineer, whether is Mechanical Engineer, Computer Engineer, or IT Engineer, now and then everybody comes across one of the vital parts of the respective industry i.e. Electronic Circuit. This electronic circuit is made or created on a special type of board, which is called PCB (Printed Circuit Board). As you can see in the above image, PCB has electronic components which are connected through conductive pathways, which are usually called Tracks. A PCB is a thin board made of Fiberglass, composite epoxy or other laminate material. Tracks are etched or printed onto a board, which connects different components on PCB, such as Diode, Resistors, Capacitors and Integrated Circuits (IC). These blue and red lines going criss-cross are the Tracks, which form electrical connections between components. And these Yellow and grey objects are actually footprints or pads of components. I Know that tracks, via and Pads are new parameters for you but don’t worry I will give you a simple answer for your understanding. Traces or Tracks: A trace is a piece of copper, think of a wire, that makes an electrical connection between 2 or more points on a pcb. Traces carry current between these two points on the printed circuit board. You can see an image where RED and BLUE are tracked. Pads: Pads are small areas of copper in predetermined shapes normally used to make a connection to a component pin. Vias: A via is a physical piece of metal that makes electrical connections between layers on the printed circuit board. Vias can carry signals or power between layers using plated through holes. Using this technology a via is formed by drilling a hole through the layers to be connected and then plating the inner surface of the drilled hole. Vias should be sized according to the traces connecting between layers and ultimately how much power it must carry. I think You got a basic idea about what exactly a PCB is… correct? So let’s move further and discuss, What are the designing tools of PCB? PCB Designing Software 1) Eagle 2) OrCAD 3) Proteus 4) KiCad 5) Altium Designer 6) EasyEDA These are some of the famous EDA software presently available in the market. One can use any one of the above lists as per their convenience of use. These are some of the famous EDA software presently available in the market. One can use any one of the above lists as per their convenience of use.EagleorCadProteusKiCadAltium DesignerEasyEDA Previous Next Application: Medical and Healthcare Industry Illumination and Lighting Industry Consumer Electronics Industry Industrial Equipment Industry Aerospace Industry Automotive Industry Safety and Security Equipment Industry Telecommunications Industry Military and Defense Summary To summarize, in this blog first, we did an introduction of PCB. Then we discussed the basics of Electronics. We introduce the Basic Concepts of PCB like Schematic, PCB layers, etc. We discuss some of the PCB designing software and applications currently used in the market. References 1.http://www.pic-control.com/pcb-design-service/ 2.https://qualityinspection.org/electronics-videos-basics-pcb-pcba-smt-process/ 3.https://kitflix.com/how-to-study-pcb-design-getting-started-with-printed-circuit-boards/ 4.https://usa.pcbpower.com/application-and-use-of-pcbs.html 5.https://www.goldphoenixpcb.com/html/Support_Resource/arc_177.html Author: Kunal Gupta
Author: Kunal Gupta
