将C与TI EZ430-RF2500开发芯片配合使用

Question

So what I am trying to do is receive a packet and print the payload to the serial port. Listening at the port is a python script that reassembles the payload and does some things with it.

Here is the code:

#include "mrfi.h"
int main(void)
{
  BSP_Init();
  MRFI_Init();
  //Initialize the serial port
  P3SEL    |= 0x30;
  UCA0CTL1  = UCSSEL_2;
  UCA0BR0   = 0x41;
  UCA0BR1   = 0x3;
  UCA0MCTL  = UCBRS_2;                     
  UCA0CTL1 &= ~UCSWRST;
  MRFI_WakeUp();
  MRFI_RxOn();
  __bis_SR_register(GIE+LPM4_bits);
}
//This is run when a packet is received
void MRFI_RxCompleteISR()
{
  uint8_t i;
  P1OUT ^= 0x02;
  mrfiPacket_t packet;
  MRFI_Receive(&packet);
  char output[] = {"                   "};
  for (i=9;i<29;i++) {
    output[i-9]='a';
    if (packet.frame[i]=='\r') {
      output[i-9]='\n';
      output[i-8]='\r';
    }
  }
  TXString(output, (sizeof output));
}

I send a packet with test data but nothing. Anybody have any insights? Also while just so you know I am learning C while I do this, so any pointers on design would also be awesome.

Thanks.

Answer 1

I don't know why your code isn't working, but here are some design hints as requested.

• Since this appears to be a hostless system, main() should most likely return void. I assume that you didn't post all of your code, as in a hostless there should also be an eternal loop in main().

• Remove all "magic numbers" from the code and replace them with #defined bitmasks or constants.

• Reduce all code inside interrupts to a minimum. The optimal interrupt only sets some flags.

• Don't use unspecified width (output[]) for arrays/strings. Embedded system design is about making things deterministic and fixed.

• Here is an example of another way to write that loop. As I have no idea what this program is supposed to do, replace the constant names with something that makes sense.

 uint8_t output[OUTPUT_N]; memset(output, ' ', SPACES_N); output[OUTPUT_N - 1] = '\\0'; for(i=0; i < SOMETHING; i++) { output[i + A_OFFSET] = 'a'; if(packet.frame[i + FRAME_OFFSET] == '\\r') { output[i + CR_OFFSET] = '\\r'; output[i + LF_OFFSET] = '\\n'; } }