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Jody
Joined: 08 Sep 2006
Posts: 182
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| PIC87J50 and RS232 (#INT_RDA) |
 Posted: Fri May 27, 2011 7:18 am |
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Hello,
I had some code working on a PIC18F4550 and want to use this on a PIC87J50...
It is a device which send some data at 9600 baud to the PIC.
So far no problem.. Test the device (RFID reader the ID20) and with the PIC18F4550 it works.
Connect it to the PIC87J50 and it isn't been able to pull the line down.
When the PIC isn't running I can see (at the scope) that there is data tranmitted. but when the PIC starts it can't pull the line low....?? I see that there is some data trying to be transmitted but it stays between the 3V and the 3,3V .....
What am I doing wrong with the setting....?????
Included the code and the header file..
Compiler version: 4.119
Checking if there is incoming data is done by setting a breakpoint at the interrupt routine. Using a ICD2...
Anybody anyclue????
Regards,
Jody
| Code: |
#include <main.h>
#include <stdlib.h>
#include <string.h>
#include <input.c>
#include <LCD_CCS.c>
int string_ready = 0;
signed int next_in = 0;
char string[20];
char string_lengte[8];
char RFID[5];
int8 first = 1;
int8 lengte_string = 0;
#int_RDA
void RDA_isr(void)
{
string[next_in]=fgetc(ID20);
if((string[next_in] == 0x0D) & (next_in > 1)) //Einde string
{
string_ready = 1;
string[next_in+1] = '\0';
next_in = 0;
}
next_in=(next_in+1);
if(next_in > 20) next_in = 0;
}
void main()
{
setup_timer_4(T4_DISABLED,0,1);
setup_oscillator(OSC_32MHZ|OSC_NORMAL|OSC_31250|OSC_PLL_OFF);
setup_uart(TRUE);
enable_interrupts(INT_RDA);
enable_interrupts(GLOBAL);
lcd_gotoxy(1,1);
printf(lcd_putc, "Test RS232");
delay_ms(5000);
while(1)
{
if(string_ready == 1)
{
lcd_gotoxy(1,1);
printf(lcd_putc, "Papagaai gezien!");
}
}
}
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| Code: |
#include <18F87J50.h>
#device ICD=TRUE
#device adc=16
#FUSES INTRC_PLL
#FUSES NOWDT //No Watch Dog Timer
#FUSES WDT128 //Watch Dog Timer uses 1:128 Postscale
#FUSES PLL5 //Divide By 5(20MHz oscillator input)
#FUSES NOXINST //Extended set extension and Indexed Addressing mode disabled (Legacy mode)
#FUSES DEBUG //Debug mode for use with ICD
#use delay(clock=32000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8,stream=ID20)
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri May 27, 2011 4:52 pm |
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Post a list of the connections between the ID-20 board and your PIC.
Post the pin numbers on each device that are connected to each other. |
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Jody
Joined: 08 Sep 2006
Posts: 182
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| Posted: Mon May 30, 2011 1:43 am |
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ID-20, pin 8, I have connected to a level converter (MAX232) pin 13 (R1IN).
MAX232 pin 12 (R1OUT) goes to pin 37 of the PIC87J50 and this is TX1, so that's wrong (I think). I have changed this into pin 38 that's RX1.
My interrupt is firing but the correct data isn't received. Now I have a oscillator settings mistake I think.
Thanks for the help!!! |
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Douglas Kennedy
Joined: 07 Sep 2003
Posts: 755
Location: Florida
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| Posted: Mon May 30, 2011 8:37 am |
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| Well string_ready is initialized (cleared) and when the ISR fills it and gets an end of line char it is set. The main routine never resets ( clears) it to the initial condition after displaying it on the LCD. Now perhaps the lcd_put routine resets it so it isn't an issue. The other issue might be that an LCD takes some time to to get itself ready for receiving commands ..there is no provision for this in the code above. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon May 30, 2011 11:33 am |
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I can't really help much more on this, because the data sheets for the
ID-12 and ID-20 are not clear on the polarity of the output signals.
For example, on this Sparkfun forum page, they say the data sheet is
incorrect. The so-called "TTL inverted" signal is not really inverted:
http://www.sparkfun.com/products/8419
If I was writing the ID-12/20 data sheet, I would nail everything down
exactly. I would show sample output waveforms for say, the character 'A'.
I would show the start bit, 8 data bits and the stop bit. I would show the
voltage levels. I would do this for both the Data 0 and Data 1 pins of
the ID-12/20. I would make everything completely obvious.
But they didn't do that, so I don't want to do anything more on this project. |
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