Posted on April 29, 2015 at 02:34Hi all,
I'm having some trouble reading more than one byte off the USART port I've configured. I'm implementing a polling receiver, as follows:
char *end_obuf = obuf+len;
char *start_obuf = obuf;
int delay_count = 0;
char newData = -1;
while(obuf < end_obuf) {
if(SET == USART_GetFlagStatus(ctx->usart, USART_FLAG_RXNE)) {
newData = USART_ReceiveData(ctx->usart);
*obuf = (char)newData;
obuf++;
delay_count=0;
} //end if there's data on RX
else {
//if there's no NEW data off the RX
if(MAX_RX_DELAY == delay_count) {
if(-1 == newData)
return UARTERR_RX_NODATA;
else
break;
}
SCAN_DelayBusymilliSecs(1); //10ms
delay_count++;
} //end if no data on RX
} //end while there's available space in obuf
When I slap a debugger on this, I get to USART_ReceiveData(<usart handle>) just the one time. I do notice the SR status register has the value 0xF8 to it (before it magically clears out to 0xC0 a short time later)
So this means, according to these #defines in my STM32 code base:
#define USART_FLAG_TXE ((uint16_t)0x0080)
#define USART_FLAG_TC ((uint16_t)0x0040)
#define USART_FLAG_RXNE ((uint16_t)0x0020)
#define USART_FLAG_IDLE ((uint16_t)0x0010)
#define USART_FLAG_ORE ((uint16_t)0x0008)
The first 3 flags are expected, but not these last 2.
How do I deal with these conditions?
I also implemented an interrupt-based receiver, but similar problem. My Rx is always in an overflow state.
Any thoughts as to what I'm doing wrong?
Thanks, Charles.
