January 25, 20242 yr Hello. For some reason, UART1 does not work for transmission, only for reception. The transmitter pin itself is definitely working, I checked by switching this pin to output mode, and then switching it to a high/low logical level, everything works properly, the level on the Pin changes. How I check the UART itself: I installed picocom, shorted the TX and RX pins, and I’m trying to see what I’m sending. For UART2 this method works as it should, but UART1 only works for reception. I realized this when I opened the TX and RX, and was able to receive incoming data sent through the USB-UART converter. Edited January 25, 20242 yr by Armbianer
January 25, 20242 yr Providing logs with armbianmonitor -u helps with troubleshooting and significantly raises chances that issue gets addressed.
January 28, 20242 yr Seems to work fine for me. root@orangepizero:~# picocom -b 115200 /dev/ttyS1 picocom v3.1 port is : /dev/ttyS1 flowcontrol : none baudrate is : 115200 parity is : none databits are : 8 stopbits are : 1 escape is : C-a local echo is : no noinit is : no noreset is : no hangup is : no nolock is : no send_cmd is : sz -vv receive_cmd is : rz -vv -E imap is : omap is : emap is : crcrlf,delbs, logfile is : none initstring : none exit_after is : not set exit is : no Type [C-a] [C-h] to see available commands Terminal ready ggggggggggggggggggggggggggggggggggggggggggggggggggggggg As the headers doesn't come preinstalled to the device, I will suggest you to check if they are soldered correctly. Also make sure you are using pin 8 and pin10 as given in the schematics. Thats 4th and 5th pin when counting from the end closest to the leds on the inner row of 26 pin headers.
January 29, 20242 yr Author Very strange things. On my board, UART1 has errors at a speed of more than 1200. The higher the speed, the more errors. That is, when the port is opened at a speed of 1200, everything is fine, at 9600 the characters are unreadable, and at 115200 nothing is displayed at all. Here is an example of displaying the sequence 1234567890 5 times at 2000 baud: Spoiler user@orangepizero:~$ sudo picocom -b 2000 /dev/ttyS1 picocom v3.1 port is : /dev/ttyS1 flowcontrol : none baudrate is : 2000 parity is : none databits are : 8 stopbits are : 1 escape is : C-a local echo is : no noinit is : no noreset is : no hangup is : no nolock is : no send_cmd is : sz -vv receive_cmd is : rz -vv -E imap is : omap is : emap is : crcrlf,delbs, logfile is : none initstring : none exit_after is : not set exit is : no Type [C-a] [C-h] to see available commands Terminal ready 1▒▒▒▒6▒8▒▒1234▒6789▒▒234567890123456▒▒9▒▒23456789▒ That is, the problem is not that UART1 TX does not send anything, but that it sends data with errors, and nothing is displayed at a speed of 115200. I have a very slow SD card. Could this be a possible reason for this behavior? Edited January 29, 20242 yr by Armbianer
January 30, 20242 yr 13 hours ago, Armbianer said: That is, the problem is not that UART1 TX does not send anything, but that it sends data with errors, and nothing is displayed at a speed of 115200. On my board I don't have the headers soldered. I just held a male to male jumper cable in place and tested the same and it worked fine. Have you soldered the headers? I wondered if there is a short somewhere. Can you share the photos of the board from both front and back?
January 30, 20242 yr 24 minutes ago, Armbianer said: https://ibb.co/0czybBH https://ibb.co/ZL6wYNb https://ibb.co/swq5HRC Those links are not reachable
January 31, 20242 yr Author https://rapidshare.io/20Rr/IMG_20240130_101637.jpg https://rapidshare.io/20Rs/IMG_20240130_101714.jpg https://rapidshare.io/20Rt/IMG_20240130_101629.jpg https://i.postimg.cc/ZR4qnB4s/IMG-20240130-101629.jpg https://i.postimg.cc/j2kqMMNB/IMG-20240130-101637.jpg https://i.postimg.cc/sx2DPkBp/IMG-20240130-101714.jpg Edited January 31, 20242 yr by Armbianer
January 31, 20242 yr 5 hours ago, Armbianer said: https://i.postimg.cc/j2kqMMNB/IMG-20240130-101637.jpg There looks like some residue around the pins, may be thats the flux. But anyways try cleaning that with some alcohol 5 hours ago, Armbianer said: https://i.postimg.cc/sx2DPkBp/IMG-20240130-101714.jpg This photo makes it look like there is something shorting tx and rx pin. Looks like a jumper or something. Not sure if what I am seeing is just lighting or something is really there, If something is there, can you try removing the same. Never mind, I guess you placed it for loopback testing.
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