AT91SAM7S256 serial port data loss

djk0125

AT91SAM7S256 serial port data loss [Copy link]

When the AT91SAM7S256 serial port receives instructions to send multiple frames of data, the last frame always loses two bytes of data! It is sent normally without serial port instructions, and no data is lost! The same instructions give different results! I am so depressed!

djk0125

void send(unsigned int add_buf,unsigned int count) { //while(!((*AT91C_US1_CSR)&(1<<4)));//ENDTX=1·￠í ENDTX=0μè′y *AT91C_US1_TPR=add_buf; *AT91C_US1_TCR=count; *AT91C_US1_PTCR = AT91C_PDC_TXTEN; while(!((*AT91C_US1_CSR)&(1<<4)));//ENDTX=1·￠í ENDTX=0μè′y } void send_sz(unsigned char *dat, unsigned char count) { unsigned char i; for(i=0;i

Check your clock source. Is it accurate?

It seems that the owner hasn't been here for a long time.

Long time no see! This problem has been solved! You can close the post!!! The problem is a common conceptual error! The CPU instruction execution speed is fast, while the serial port transmits data at the baud rate! The main program has been tossing back and forth, and the serial port has not finished the data transmission, and the main program is tossing the serial port send buffer again! Coincidentally, the send buffer is reassigned! As a result, data is lost! The solution is to check whether all the data has been sent when the serial port sends it, and then perform other operations! This will cause waiting, and it is okay if there are not many tasks!

AT91SAM7S256 serial port data loss

leifengfirst

Check your clock source. Is it accurate?

港定

It seems that the owner hasn't been here for a long time.

djk0125

Long time no see! This problem has been solved! You can close the post!!! The problem is a common conceptual error! The CPU instruction execution speed is fast, while the serial port transmits data at the baud rate! The main program has been tossing back and forth, and the serial port has not finished the data transmission, and the main program is tossing the serial port send buffer again! Coincidentally, the send buffer is reassigned! As a result, data is lost! The solution is to check whether all the data has been sent when the serial port sends it, and then perform other operations! This will cause waiting, and it is okay if there are not many tasks!