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c0de
Joined: 14 May 2007
Posts: 14
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| i2c problem with PIC16F876 and MD03 DC motor driver |
 Posted: Sat Jun 07, 2008 1:54 am |
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Hello.
I have some problems in driving a dc motor with a PIC16F876 and MD03 DC motor driver. The MD03 is using a PIC16F872 in slave mode. Theoretically, all I have to do is to set my PIC on i2c master mode and control the DC motor using i2c_* functions. I configured the MD03 to work on 0xB0 address and tried to start the motor... nothing happens... Here is the master program:
| Code: |
#include <16F876.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#use I2C(master, SDA=PIN_C4, scl=PIN_C3)
unsigned int i=0, pin_state=0, state=0, last_state=0;
void main() {
delay_ms(1000);
printf("Starting up\n");
printf("Delaying 5 seconds...\n");
delay_ms(5000);
set_tris_b(0x01);
output_low(PIN_B1); // Select MUX157
output_low(PIN_B2); // A
output_low(PIN_B3); // B
output_low(PIN_B4); // C
i2c_start();
i2c_write(0xB0);
i2c_write(0x00);
i2c_write(0x01);
delay_ms(5000);
i2c_stop();
while ( 1 )
{
for (i = 0; i<=7; i++)
{
if( !bit_test(i,0) )
{
output_low(PIN_B2);
delay_us(20);
}
else
{
output_high(PIN_B2);
delay_us(20);
}
if( !bit_test(i,1) )
{
output_low(PIN_B3);
delay_us(20);
}
else
{
output_high(PIN_B3);
delay_us(20);
}
if( !bit_test(i,2) )
{
output_low(PIN_B4);
delay_us(20);
}
else
{
output_high(PIN_B4);
delay_us(20);
}
pin_state = input(PIN_B0);
if (pin_state)
bit_set(state,i);
else
bit_clear(state,i);
}
delay_us(20);
if ( state != last_state )
{
output_high(PIN_B5);
printf("Input = %3u\n", state);
last_state = state;
delay_us(20);
}
else
{
output_low(PIN_B5);
delay_us(20);
}
}
printf("Done :)\r\n");
delay_ms(20);
}
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The while loop is used to read some digital inputs of 3 multiplexers and works fine. The master SDA is connected to slave SDA ... same for SCL.
I wonder if there is something else that needs to be set in order to get it work.
Thank you |
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horkesley
Joined: 20 Feb 2007
Posts: 48
Location: Essex UK
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| Posted: Sat Jun 07, 2008 1:59 am |
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Hi,
At the risk of offending you, a simple question, have you got pull up resistors on SDA, SCL?
Regards
_________________
Horkesley Electronics Limited |
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c0de
Joined: 14 May 2007
Posts: 14
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| Posted: Sat Jun 07, 2008 2:47 am |
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| horkesley wrote: | Hi,
At the risk of offending you, a simple question, have you got pull up resistors on SDA, SCL?
Regards |
Hi. You are not offending me  I'm a beginner and I accept any advices. The answer is no... I dont have pull ups on SDA and SCL. I'll try with pullups and come back with the result.
Thank you:) |
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