M1284P USB to serial not communicating

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This is a custom board but since I'm using the Arduino framework I thought this might be the best place, even though I'm not sure if this is a hardware or software issue.

 

I have a CH340E hooked up to PD0 & PD1 but I'm unable to send or read data through them. The chip does receives indicated by the LED connected to the TNOW pin but it doesn't appear to go anywhere. My computer detects it without a problem.

 

One potential issue is I'm using the internal clock at 8MHz (without division) but even then I should at least get some globs of data I feel like? I don't have an oscilloscope available but I'm unable to see any voltage on PD0 or PD1 making me feel this might be a software thing.

 

I've tried this code

#include <Arduino.h>
void setup() {
   Serial.begin(9600);
}

void loop() {
   int i;
   while(1) {
      Serial.write("test\n");
      delay(5000);
   }
}

and also messed around with SoftwareSerial but to no help.

Fuses:  (E:FF, H:99, L:C2)

 

Sorry for the bad file names, thought it would show a preview :)

SSS = PCB

issss = Schematic

 

Attachment(s): 

This topic has a solution.
Last Edited: Mon. Jun 7, 2021 - 09:14 AM
This reply has been marked as the solution. 
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You need to connect USB adaptor Tx to MCU Rx and USB adaptor Rx to MCU Tx. Been there, made that error!

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

Last Edited: Sun. Jun 6, 2021 - 11:54 PM
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woops, that embarrassing. Time for some PCB surgery.

 

Thanks!