AVR-Chat

For transmit, does checking TXC instead of UDRE limit the max 
transmit speed?  And what is the lag between writing to UDR and it 
getting put into the transmit shift register?

Mike


--- In AVR-Chat@yahoogroups.com, JChavez@s... wrote:
> 
> 
> 
> 
> 
> 
> It depends on what AVR you are using however this shoul help..
> 
> void RS232_init(void)
> {
>    outp(0x18, UCR);
>    //outp((char)UBR, UBRR);
>    outp(8, UBRR);       // 12=38400 8=57600 3=115200
>    sbi(USR, TXC);       // UART Trnsmt complete (clear TXC flag but 
logical
> 1)
> 
>    cbi(DDRD, PD0);      // RXD (UART input line)
>    sbi(DDRD, PD1);      // TXD (UART ouput line)
> 
> }
> 
> uint8_t cin(void)
> {
>    loop_until_bit_is_set(USR,RXC);
>    return(inp(UDR ));
> }
> 
> void cout(uint8_t a)
> {
>    outp(a, UDR);
>    loop_until_bit_is_set(USR,TXC);
>    sbi(USR, TXC);       // UART Trnsmt complete (clear TXC flag but 
logical
> 1)
> }
> 
> 
> then  in main ..
> 
>     cout((cin());
> 
> Hope this helps..
> 
> Javier