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mcisabel
Joined: 28 Jul 2005
Posts: 3
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| Software uart baud rate change |
 Posted: Fri Aug 19, 2005 8:18 am |
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Hi, I had a problem, I'm working with two software uart and I would like to change the baud rate when I want doing a #use rs232 with a diferent baud rate but in the same stream that I allready had, but it doesn`t work and I don`t understand why.
#use rs232 (baud=9600, xmit=TX1, rcv=RX1, STREAM=COM_A, disable_ints) //PIC USART (AL PLC)
#use rs232 (baud=9600, xmit=TX2, rcv=RX2, STREAM=COM_B, disable_ints) //RS-232 maestro
#use rs232 (baud=9600, xmit=TX3, rcv=RX3, STREAM=COM_C, disable_ints) //RS-232 TTL al radio modem
#use rs232 (baud=9600, xmit=TX4, rcv=RX4, STREAM=COM_D, disable_ints) //RS-485
void uart_speed(char s, int puerto)
{
if(puerto==2)
{
if(s=='1')
{
delay_cycles(1);
#undef COM_B
#use rs232 (baud=19200, xmit=TX2, rcv=RX2, STREAM=COM_B, disable_ints
}
}
}
void main()
{
setting_uarts_speed(2);
enable_interrupts(INT_RB);
ext_int_edge(0,H_TO_L);
clear_interrupt(int_ext);
enable_interrupts(int_ext);
enable_interrupts(GLOBAL);
port_b_pullups(true);
while(mantente==0)
{
}
} |
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ALFA 705
Joined: 03 Jun 2005
Posts: 9
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| Posted: Sat Aug 20, 2005 5:53 am |
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Hola,
Try to use: set_uart_speed (baud, [stream])
That's :
set_uart_speed(19200,COM_A);
set_uart_speed(9600,COM_B);
...
You can change uart speed on each "COM".
I hope this can help you.
Salud !
ALFA 705 |
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Ttelmah
Guest
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| Posted: Sat Aug 20, 2005 6:53 am |
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| ALFA 705 wrote: | Hola,
Try to use: set_uart_speed (baud, [stream])
That's :
set_uart_speed(19200,COM_A);
set_uart_speed(9600,COM_B);
...
You can change uart speed on each "COM".
I hope this can help you.
Salud !
ALFA 705 |
No.
Look carefully at the manual entry. Note 'only applies to devices with the hardware UART' (should really say 'only applies to the hardware UART'...).
You cannot use 'set uart speed' on a software UART.
The problem is trying to be a bit 'too smart' in the original code. The USE RS232 command, creates the code for a software UART 'inline' when this is used. Unfortunately, this means you cannot switch 'on the fly'. Instead use something like this:
| Code: |
#use rs232 (baud=9600, xmit=TX2, rcv=RX2, STREAM=COM_B, disable_ints) //RS-232 maestro
#use rs232 (baud=19200, xmit=TX2, rcv=RX2, STREAM=COM_BFAST, disable_ints) //RS-232 maestro at 19200bps
#define 9600bps (0)
#define 19200bps (1)
int8 speed=9600bps;
#define soft_set_speed(rate) speed=rate
void putc_comb(char s) {
switch (speed) {
case 9600bps:
fputc(COM_B,s);
break;
case 19200bps:
fputc(COM_BFAST,s);
break;
//expand for more rates if needed
}
}
soft_set_speed(9600bps);
printf(putc_comb,"Sent at 9600bps");
soft-set_speed(19200bps);
printf(putc_comb,"Sent at 19200bps");
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Best Wishes |
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