CH32V003 UART issue

[castrofernando]

I'm not sure ig it's a issue, althought I've tried to make UART works in CH32V003F4P6-R0 evt board without success using arduino framework. For a reason that I didn't discover yet, TX and RX are not working properly, so I could not receive or transmit anything. Below is the code I'm trying:

#include <Arduino.h>

#define PIN_SERIAL_RX         PD6
#define PIN_SERIAL_TX         PD5

void setup() {
  Serial.begin(115200);
  Serial.setPins(PIN_SERIAL_RX, PIN_SERIAL_TX);
  delay(1000);
  Serial.println("Serial Started");
}

void loop() {
  if(Serial.available() > 0) {
        Serial.print("I have received: ");
        while(Serial.available()) {
            char c = Serial.read();
            Serial.print(c);
        }
        Serial.println();
    }
}

Am I missing something? It's the first time I try this hardware, so I still discoverying it. I also did not found many other examples/tutorials using Serial with arduino framework for this hardware.
I'm sure that I have connected properly TX and RX, because using noneos-sdk the UART is working properly with the code below.

#if defined(CH32V00X)
#include <ch32v00x.h>
#elif defined(CH32V10X)
#include <ch32v10x.h>
#elif defined(CH32V20X)
#include <ch32v20x.h>
#elif defined(CH32V30X)
#include <ch32v30x.h>
#endif
#include <stdio.h>
#include "debug.h"

int main(void)
{
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
	SystemCoreClockUpdate();
	Delay_Init();
	USART_Printf_Init(115200);
	Delay_Ms(1000); // give serial monitor time to open
	printf("SystemClk: %u\r\n", (unsigned)SystemCoreClock);
	#if defined(CH32V30X)
	printf("ChipID: %08x\r\n", (unsigned)DBGMCU_GetCHIPID());
	#else
	printf("DeviceID: %08x\r\n", (unsigned)DBGMCU_GetDEVID());
	#endif
	printf("This is printf example\r\n");

	while (1)
	{
		Delay_Ms(1000);
		printf("Program over, press reset button\r\n");
	}
}

void NMI_Handler(void) __attribute__((interrupt("WCH-Interrupt-fast")));
void NMI_Handler(void) {}
void HardFault_Handler(void) __attribute__((interrupt("WCH-Interrupt-fast")));
void HardFault_Handler(void)
{
	while (1)
	{
	}
}

I really appreciate a direction to debug it. Thank you.

[kubakubakuba]

Any development on this? I am able to send data from the CH32, but not receive. Bizzare...

[kubakubakuba]

Okay, after a while debugging it (3 days to be honest), I got to this:

#include <Arduino.h>

char cmd_buffer[32];
uint8_t buf_ptr = 0;

void processCommand(char* cmd) {
    if (strcmp(cmd, "PING") == 0) {
        Serial.println("PONG");
    } 
    else if (strcmp(cmd, "RUNTIME?") == 0) {
        Serial.print("RUNTIME:");
        Serial.println(millis());
    }
    else {
        Serial.print("UNKNOWN_CMD:");
        Serial.println(cmd);
    }
}

void setup() {
    Serial.begin(9600); 
}

void loop() {
    //read from hw directly
    if (USART1->STATR & USART_STATR_RXNE) {
        char incomingChar = USART1->DATAR & 0xFF; 

        if (incomingChar == '\n' || incomingChar == '\r') {
            if (buf_ptr > 0) {
                cmd_buffer[buf_ptr] = '\0'; 
                processCommand(cmd_buffer);
                buf_ptr = 0; 
            }
        }

        else if (buf_ptr < 31) {
            cmd_buffer[buf_ptr++] = incomingChar;
        }
    }
}

so I guess there is a bug in the platform-ch32v? Serial.available() does not work for me at all.

Good to note that you need to disconnect the RX/TX pins of the WCH link, or it acts a bit shy and does not want to receive anything.