Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [loopback]

Connecting a full-duplex transceiver to itself to test its functionality, or otherwise making a local signal connection instead of one to another device. For feedback loops, use [feedback] or [control-loop] instead.

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Testing an FTDI chip

I have an FTDI chip (reference manual here) that translates USB from a PC to an SPI channel connected to an FPGA. I would like to test that the communication path between the PC and the FPGA is functional. Probably the easiest approach would be to…
Randomblue
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STM32 USART loopback

Is it possible to connect the Rx and Tx pins of the same USART or on two different USARTs on an STM32 discovery board to make a loopback and test the USART?
rxjsisfine
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SPI loopback with DMA

I am using STM32F4 discovery board and I am attempting to get SPI loopback with DMA. I have successfully got an "SPI-only" loopback running, but now I want use DMA in addition with the SPI, here are the functions that I am using: Initialisation of…
fedi
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SPI Loopback value received is half of transmitted value

I am testing SPI of my PIC24E512GU814 microcontroller. In order to test, I connected MOSI to MISO. I wrote the following code for SPI initialization: SPI3CON1 = 0; SPI3CON1bits.CKE = 1; SPI3CON1bits.SPRE = 7; SPI3CON1bits.PPRE =…
md.jamal
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How does the loopback on a non-retriggerable monostable work?

I understand how to connect a monstable multivibrator to be in the non-retriggerable mode. Just loopback the /Q to the falling edge input or the Q to the rising edge output) as in the following picture (taken from the MC14528B datasheet). Now I…
Francis Poirier
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STM32 CAN bus Rx interrupt only triggers in loopback mode

I'm designing the CAN interface for a STM32F042C4T6 to be able to receive and send messages. I've tested my code and everything seems to work perfectly fine in loopback mode. However, when I hook up two STM32's together (with CAN transceivers on…
achilles7744
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FPGA Loopback (two pins) - What is the way to create a pullup to set one (or the other) pin to high when it is tri-stated to high impedance?

I need to wire up the four GPIO pins (connected to the FPGA pins) in a way that keeps the value of the pin at a pulled up value of appropriate voltage. I have an option to use the pullup resistors. When not sending or receiving data, both…
Vahe
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STM32 how to test CAN interface without a transmitter connected?

I'm doing some work on STM32 board, and I don't have a CAN transceiver connected to my STM (yet). CAN_RX / CAN_TX pins are just hanging in the air. Is it possible to at least test the loopback mode in this configuration or just send packets and…
floppydisk
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How Serial Port Loopback Test work internally/underneath?

Actually I've asked my question on StackOverflow, but I really think it belongs here. Here it is anyway: When doing a Serial Loopback Test on a USB Port (assume COM1) using Hyperterminal or any other serial terminal (i.e. PuTTY), you can verify that…
faressalem
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