Trigger the data output from external signal

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1

Hi all,

I'm using UART, TX pin1, to output serial data. The oscillator is 16M on the broad. And I output the data by 1M, which I can see the 1M clock on pin4(every rising edge-->a bit output).

uint8_t  g_Buffer1[] = {0xAA,0xBB,0xCC};
uint8_t count1 = 0;

void setup() {
  Serial.begin(9600); // initialize serial
  USART_MSPIM_Init(); // initialize MSPIM mode
  SPCR = (1 << SPE);  // enable SPI
  TIMSK0 = 0;         // disable timer0
}

void loop() {
    if ((UCSR0A & 32) != 0) {    // transmit when data register empty
        UDR0 = g_Buffer1[count1]; //transfer code
        count++;
    }
}

void USART_MSPIM_Init()
{
  UBRR0H = 0;
  UBRR0L = 0;
  DDRD |= _BV (4);                                             // XCK as output enables master mode
  UCSR0C = (1 << UMSEL01) | (1 << UMSEL00) | (0 << UCPHA0) | (0 << UCPOL0); // Master SPI, mode 0
  UCSR0B = (1 << RXEN0) | (1 << TXEN0);                        // Enable receiver and transmitter
  UBRR0L = 7;                                                  // 1MHz XCK on pin 4
}

Is it possible that I can trigger the data output from external 1M signal inputting to the broad?
(The present output rate 1M is what I desired, but the timing is not)

Thanks.

2

You could trigger an interrupt at 1MHz but.... interrupts have overhead that takes about 4 micros for each interrupt so no 1MHz response is possible.

Try looking at the faster Teensy boards, last I saw ran 180MHz which gives enough cycles to do a bit between ticks.