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neverlog
Joined: 02 May 2010
Posts: 36
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| 1 software uart and 1 hardware uart |
 Posted: Tue Jul 06, 2010 5:43 am |
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Dear All,
I am new to PIC and CCS.
I have one project as below:
RFID Reader <===>PIC<====>PC
My RFID reader needs to get command from PIC then it will return data to PIC, at the same time I need to display it on the PC, and PIC will be getting command from PC for other purpose.
I don't need full-duplex, half duplex will be just fine.
I have problem using 1 software uart and 1 hardware UART. I am using 16F877A.
I am trying to use #int_rda and #int_tbe for hardware uart,
I am using #int_ext (PIN_B0) for my receive (Software UART), does there have any solution for transmit buffer(software uart)?
my communication for reader to PIC and PIC to PC need to be 2 way, most of the thread I read is one way.
Can anybody please help? Thanks in advance.
My next phase is, I will need to link all the PIC through RS485 because there will be total of 16 (reader+PIC) need to be controlled by a PC. |
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neverlog
Joined: 02 May 2010
Posts: 36
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| Re: 1 software uart and 1 hardware uart |
| Posted: Tue Jul 06, 2010 6:04 am |
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This is my code, I just can't make it running. At the PC side, it won't display the return data from reader.
| Code: |
//Auto Mode Software and Hardware UART for EMR/DUR300 by Lam
#include <16F877a.h>
#fuses hs,noprotect,nowdt,nolvp
//#device adc=8
#use delay(clock=20000000) //20mhz
#use rs232(baud=19200, xmit=PIN_B1, rcv=PIN_B0, stream=reader)
#use rs232(baud=19200, xmit=PIN_C6, rcv=PIN_C7, errors,stream=pc)
//#include <stdlib.h>
//#include <stdio.h>
//#include <string.h>
#pragma zero_ram //interesting command
//Software UART================================================
#define SU_BUFFER_SIZE 32
BYTE SU_buffer[SU_BUFFER_SIZE];
BYTE SU_next_in = 0;
BYTE SU_next_out = 0;
#int_ext
void SU_serial_isr() {
int SU_t;
SU_buffer[SU_next_in]=fgetc(reader);
SU_t=SU_next_in;
SU_next_in=(SU_next_in+1) % SU_BUFFER_SIZE;
if(SU_next_in==SU_next_out)
SU_next_in=SU_t; // Buffer full !!
}
#define SU_bkbhit (SU_next_in!=SU_next_out)
BYTE SU_bgetc() {
BYTE SU_c;
while(!SU_bkbhit) ;
SU_c=SU_buffer[SU_next_out];
SU_next_out=(SU_next_out+1) % SU_BUFFER_SIZE;
return(SU_c);
}
//HArdware UART================================================
#define BUFFER_SIZE 32
BYTE buffer[BUFFER_SIZE];
BYTE next_in = 0;
BYTE next_out = 0;
#int_rda
void HU_serial_isr() {
int t;
buffer[next_in]=getc();
t=next_in;
next_in=(next_in+1) % BUFFER_SIZE;
if(next_in==next_out)
next_in=t; // Buffer full !!
}
#define bkbhit (next_in!=next_out)
BYTE bgetc() {
BYTE c;
while(!bkbhit) ;
c=buffer[next_out];
next_out=(next_out+1) % BUFFER_SIZE;
return(c);
}
//main program================================================
void main() {
int i;
char c;
enable_interrupts(global);
enable_interrupts(int_rda);
enable_interrupts(int_ext);
ext_int_edge(H_to_L);
printf("\r\n\Running...\r\n");
// The program will delay for 10 seconds and then display
// any data that came in during the 10 second delay
//RF ON Command
do {
delay_ms(2000);
fputc(0x40,reader);
delay_ms(1);
fputc(0x02,reader);
delay_ms(1);
fputc(0x00,reader);
delay_ms(1);
fputc(0x41,reader);
delay_ms(1);
fputc(0x01,reader);
delay_ms(1);
fputc(0x42,reader);
delay_ms(1);
delay_ms(50);
for (i=0;i<5;i++) { //Reader will return 5 bytes
printf("%02x", SU_bgetc());
}
} while (TRUE);
} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Jul 06, 2010 1:57 pm |
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| Quote: | #use rs232(baud=19200, xmit=PIN_C6, rcv=PIN_C7, errors,stream=pc)
#int_rda
void HU_serial_isr()
{
buffer[next_in]=getc();
.
.
.
}
printf("%02x", SU_bgetc());
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In the code above, you have a specified a stream for the PC side,
but you are using non-stream functions. You need to use fgetc()
and fprintf().
| Quote: | enable_interrupts(global);
enable_interrupts(int_rda);
enable_interrupts(int_ext);
ext_int_edge(H_to_L); |
Here you are setting the interrupt edge after you have enabled INT_EXT
interrupts. Ideally, the edge should be set up before you enable
interrupts. |
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neverlog
Joined: 02 May 2010
Posts: 36
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| Posted: Tue Jul 06, 2010 7:35 pm |
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Thank you for your help, PCM Programmer.
I have changed it, but it still doesn't work.
At least I can see it print out "Running" on the screen,
Are we allow to use more than 1 interrupts in the PIC?
I am using compiler version 3.181 |
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neverlog
Joined: 02 May 2010
Posts: 36
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| Posted: Tue Jul 06, 2010 7:51 pm |
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I need to put the delay_ms(1) after each command, I wonder why I must?
Do software uart have something like #int_TBE in hardware uart?
Please help me. Thank you. |
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neverlog
Joined: 02 May 2010
Posts: 36
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| Posted: Wed Jul 07, 2010 10:53 pm |
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My program is running, but now I have new problem.
When I turn on my PIC, the PIC will transmit FF00. It happens everytime I start the PIC. It is ok when I reset the PIC.
Does anyone know how to clear the transmit buffer for the first time the PIC is on?
Please help. Thanks in advance. |
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