RemdesKVM/usbkvm/usbkvm_fw3/usbkvm_fw3.ino

/*
  RemdesKVM USB-KVM
  Firmware for PCB design v4 or above

  Author: tobychui

  Upload Settings
  CH552G  
  24Mhz (Internal)
*/
#include <Serial.h>

uint8_t c = 0x00;

// Send a CH9329 cmd via UART0
void send_cmd(uint8_t cmd, uint8_t* data, uint8_t length) {
  uint8_t sum = 0;
  Serial0_write(0x57);
  sum += 0x57;
  Serial0_write(0xAB);
  sum += 0xAB;
  Serial0_write(0x00);

  Serial0_write(cmd);
  sum += cmd;
  Serial0_write(length);
  sum += length;
  for (int i = 0; i < length; i++) {
    Serial0_write(data[i]);
    sum += data[i];
  }
  Serial0_write(sum);
}

// flush the serial RX (blocking)
void flush_cmd_resp() {
  delay(100);
  while (Serial0_available()) {
    uint8_t b = Serial0_read();
    USBSerial_print("0x");
    if (b < 0x10) USBSerial_print("0");
    USBSerial_print(b, HEX);
    USBSerial_print(" ");
  }
  USBSerial_println("");
}

// Set the USB descriptor exposed to the slave device
void setup_keyboard_chip_cfg() {
  //Set manufacturer string
  uint8_t manufacturer_string[9] = { 0x00, 0x07, 'i', 'm', 'u', 's', 'l', 'a', 'b' };
  send_cmd(0x0B, manufacturer_string, 9);
  flush_cmd_resp();
  //Set product string
  uint8_t product_string[11] = { 0x01, 0x09, 'R', 'e', 'm', 'd', 'e', 's', 'K', 'V', 'M' };
  send_cmd(0x0B, product_string, 11);
  flush_cmd_resp();
}

//This function handles the incoming data from CH9329
void handle_cmd_processing() {
}

//This function will handle the incoming cmd from RemdesKVM control software
//return 0x00 if success and 0x01 if error
void handle_ctrl_cmd() {
}

void setup() {
  //Serial0_begin(9600);  // CH9329 UART default baudrate (uncomment this before running -cfgchip)
  Serial0_begin(19200);
  delay(100);
  setup_keyboard_chip_cfg();
}

void loop() {
  // Read characters into buffer
  if (USBSerial_available()) {
    c = USBSerial_read();
    Serial0_write(c);
  }

  if (Serial0_available()) {
    c = Serial0_read();
    USBSerial_write(c);
  }
}