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meepa123
Joined: 27 Feb 2007
Posts: 17
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| New I2C trouble, 18f4550 master versus 18f2550 slave. |
 Posted: Sun Mar 04, 2007 6:48 pm |
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Master: 18f4550 @48mhz / 20mhz xtal
| Code: |
#include <18f4550.h>
#fuses HS,PLL5,CPUDIV1,NOWDT,PUT,NOLVP
#use delay(clock=48000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#build (reset=0x04,interrupt=0x08)
int encoder_value=0,encoder_target=0;
int1 encoder_bit=0,encoder_bit2=0,encoder_task=0;
int motortask;
#include <lcdbot.c>
#use i2c(master, sda=PIN_C4,scl=PIN_C5,slow)
int i2c_data[10];
int tmp;
int q;
void main()
{
setup_psp(PSP_DISABLED);
set_tris_c(0x00);
output_low(PIN_C4);
output_low(PIN_C5);
set_tris_c(0x30);
//setup_timer_0 (RTCC_INTERNAL|RTCC_DIV_4);
//enable_interrupts(GLOBAL);
//enable_interrupts(INT_TIMER0);
lcd_init();
printf(LCD_PUTC,"START!!");
delay_ms(1000);
lcd_putc('\f');
while(1)
{
printf(LCD_PUTC,"Start2");
delay_ms(1000);
lcd_putc('\f');
i2c_start();
printf(LCD_PUTC,"1");
delay_ms(1);
i2c_write(0xa0);
printf(LCD_PUTC,"2");
delay_ms(1);
i2c_write(0x00);
printf(LCD_PUTC,"3");
delay_ms(1);
i2c_write(0x80);
printf(LCD_PUTC,"Datos");
lcd_putc('\f');
i2c_stop();
printf(LCD_PUTC,"Dato enviado");
delay_ms(1000);
lcd_putc('\f');
i2c_start();
i2c_write(0xa0);
i2c_write(0x00);
i2c_start();
i2c_write(0xa1);
tmp=i2c_read();
printf(LCD_PUTC,"%u",tmp);
i2c_stop();
}
}
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I think slave code is not necessary at this moment, for the reasons i'm explaining now. The chip starts working, shows START!!! , START2, and then shows 1. And then nothing happens. The chip hung. So the thing gets hung in i2c_write, i suppose. It's not possible to use hardware MSSP, because of the needed pinout.
I've looked into the problem with an analogic scope, and i found out that both SDA and SCL stay high all the time. 2K2 pullups are used.
I hope you can help me. |
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unnamedplayer
Guest
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| Posted: Mon Mar 05, 2007 4:19 pm |
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| i heard hardware ssp gives less trouble than soft one.. |
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rnielsen
Joined: 23 Sep 2003
Posts: 852
Location: Utah
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| Posted: Mon Mar 05, 2007 5:55 pm |
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Odds are, if you are using another PIC as the slave, the code inside it is not working properly. The slave can hold the I2C bus in a 'busy' state and the master will just set there twiddling it's thumbs until it is released. Look through this forum and look for the many examples for slaves. Try a few and see if you can get them to work. Then, once you find one that works, modify it little-by-little until you have it doing what you want.
Ronald |
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meereck
Joined: 09 Nov 2006
Posts: 173
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| Posted: Mon Mar 05, 2007 7:27 pm |
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| Dont know whether it helps, but fuse should be HSPLL instead of HS. |
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