USB to RS485 converter: Auto enable control
I have been trying to program infineon mcu via usb to rs485 converter. Procedure to check mcu is working fine: Query command sent using hercules : 0×80 Response sent by mcu : 0×55 (correct response) I...
View ArticlePIC18f45J50 2nd Serial port?
I am working on a GPS tracker Project where i need to interface with a GPS module and a UMTS module for 3g connectivity. with this i need 2 serial ports on a single microcontroller. For this...
View ArticleMeasuring if a transistor can work for SPI/UART when doing logic level...
I need to convert 3v3 to 5V and 5V to 3v3 for SPI/UART. I found many options. But I’m still confuse whats good for me. Because Transistors and few other components has rise and fall time. I want to...
View ArticleUART voltage on RX pin?
I bought an uart ttl to usb 2.0 adapter on ebay which I tried out yesterday with no luck. I measured all the pins and found to my surprise that the RX pin actually carries 3.3V. This can’t be right as...
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STM32F3 Discovery reading values from sensor using I2C
I need to read values from on-board LSM303DLHC (connected via I2C) sensor and send them through UART. UART part is working but PuTTy shows: “S▒▒” every restart… Can anyone tell me what’s wrong? I know...
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FTDI2232d + TM4C1294 configurations
I posted this question before, but I am still struggling with this. I captured a schematic and others in this time so it should be more clear to see what’s going on. I was given a custom board...
View ArticleCan't run 460800 baude rate on Nexys2
I have Nexys2 Spartan 3E board and I am running Ken Chapman’s UART IP core, I need to transmit data to another device at a baude rate of 460800. I was successful in sending data at 115200 and 9600...
View ArticleConvert ASCII represented HEX into HEX
I have a question which I was unable to solve but it seemed trivial. I am getting a stream of characters from a processor over UART and this stream represents a JPEG file. I captured this stream, as...
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SLEEP_MODE_ADC interfering with USART (and beep)
On an AVR ATmega328P, once per second I am doing 3 AD conversions immediately following each other with 16x oversampling using SLEEP_MODE_ADC like this: EMPTY_INTERRUPT(ADC_vect); uint16_t...
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MIDI IN : many circuits
I’m building a MIDI IN to serial port RX cicruit (for Raspberry Pi, or Arduino, or anything else…) using a 6N138 optoisolator. But I find many different circuits, I don’t know why there are so...
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UART: two transmitters, single slave
simulate this circuit – Schematic created using CircuitLab My circuit is shown above – where I have the TXD pin of an ATMEGA connected to the RXD pin of a BT slave. Both devices operate on 3.3V – so...
View Article74HCT244 UART level translator, how would the circuit look?
I am building a UART 3.3V to 5V Level translator between a Raspberry Pi and a ATMega328. The 74HCT244 is my choice of translator but I can’t find a good example of of hooking it up. Am I right that I...
View ArticleWhat IRQ to use for USART transmission handling under SAM3x8e?
I’ve made the USART support for SAM3x8e arduino based board. The MCU has TXRDY, ENDTX, TXEMPTY, TXBUFE interrupts. What would be the best choice to be used in IRQ driven transmission handling? Now I...
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FTDI UART programming (first steps)
Im currently trying to leave the arduino board aside and starting program microcontrollers on pcb boards via programming pins, im using an ATMEGA328u from this premade board, For starters im trying to...
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How to troubleshoot serial communication?
I connected my computer to a RM-BR300 controller to read its data, to try and mimic its functionality in the future. I’m using RealTerm and a USB to RS422 converter for the job – here’s the result:...
View ArticleJitter in UART start-bit
Experimental setup: STM32F103RB microcontroller, Keil uVision 4.72, USART2 on PA.2, PA.3. Experiment: initialize USART for 9600 baud/s, initialize PORTA, initialize SysTick (for delays, interrupt every...
View ArticleU(S)ART/SPI/I2C – any common/prevalent/recommended connectors?
Good morning everyone! I’m currently building the board with the STM32F417 microcontroller, and I want to have separate (out-of-GPIO) I2C, SPI, UART and USART outputs on the board. But I’m lost on what...
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Bitwise operation for UART, AVR
I’m trying to work on UART for AVR. After setting the baud rate registers UBRRnX, I’m trying to configure the UCSRnA register. I’m trying to set the 2nd bit, U2XO. Which is the right way to do it?...
View ArticleError in turning ON the LED using UART in PIC32
I have a PIC32 starter Kit & IO Expansion Board. PIC32 Starter Kit has 3 LEDs on baord LED1 LED2 LED3 . I have made a uart program such that if someone presses 1 on the keyboard, this 1 will be...
View ArticleLow cost UART over fibre
I need to extend an existing 5V UART over fibre for isolation reasons. Digital isolators / optos are no good as I need more isolation than that (0.1pF coupling max. from one side to the other). UART...
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