AT90S2313 GNU Compiler UART Question

the

I'd rewrite it to use interrupts. See Volker Oth's gcctest program 4.

Peter

If it does't work polling, then something very fundamental is broken (e.g. wrong register addresses). Adding interrupts to the problem isn't going to make things better.

the

Another thought... would it help to change this line?

into outb(UDR,data); /* Start transmission

Peter

Hello,

Here is the current code.

I'm using volatile variables

===========================

#define __AVR_AT90S2313__ #include

#define UARTCONTROL 0x18 /* b00011000 0- RXCIE interrupt disabled 0- TXCIE interrupt disabled 0- UDRIE interrupt disabled 1- RXEN Receiver enabled 1- TXEN Transmitter enabled 0- 9 bit characters (for parity) disabled 0- Rest (8th bit I/O) ignore */ #define BAUDRATE 51 /* 8MHz oscillator - 9600 baud

void initUART() { outp(BAUDRATE, UBRR); outp(UARTCONTROL, UCR); }

void TransmitByte (volatile unsigned char data) { volatile unsigned char uS;

{ uS = inp(USR); } while (!(uS & 0x40)); outp(data , UDR); }

int main() { volatile unsigned char uartStatus; volatile unsigned char serialData; initUART();

TransmitByte ('b'); TransmitByte ('A'); TransmitByte ('h'); TransmitByte ('o'); TransmitByte ('i'); TransmitByte ('j'); TransmitByte ('d'); TransmitByte ('e');

============== The output is only 'bA' that's all !

Regards,

Bernard

Bernard Stibbe wrote: ...

It looks that you are using outdated version of GNU toolchain. Use the latest stable versions, please. At least if you want to get real support from other users.

#include

#define UARTCONTROL _BV(RXEN)|_BV(TXEN)

void initUART() { UBRR = BAUDRATE; UCR = UARTCONTROL; }

void TransmitByte (unsigned char data) { while (bit_is_clear(USR, UDRE)) ; UDR = data; }

or

void TransmitByte (unsigned char data) { while (bit_is_clear(USR, TXC)) ; USR |= _BV(TXC); UDR = data; }

Regards,

Huh? You read the USR once, then execute an empty while loop????