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Memristor
Guest
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| weird readings in a HMC6352 |
 Posted: Fri Jan 16, 2009 8:18 am |
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hi!
I bought a digital compass, the hmc6352, it works fine.
I changed the operational mode, and then i try to read it from the EEPROM and from the RAM, but i get weird numbers like 12, 3, 4,
(I expect 82=0x52);
| Code: |
#include <16F873A.h>
#fuses HS, NOPROTECT, NOWRT, NOLVP
#use delay(clock=20000000)
#use i2c(Master, sda=PIN_C4, scl=PIN_C3)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, parity=N, bits=8)
void changemode(){
int raam;
i2c_start();
i2c_write(0x42);
i2c_write(0x47);//write to RAM
delay_us(80),
i2c_write(0x74);//RAM address
delay_us(80);
i2c_write(0x52);//continuous operational mode (0b01010010)
i2c_stop();
delay_us(80);
i2c_start();
i2c_write(0x42);
i2c_write(0x67);//read from RAM
delay_us(80);
i2c_write(0x74);//RAM address
i2c_stop();
delay_us(80);
i2c_start();
i2c_write(0x43);
raam=i2c_read();
i2c_stop();
printf(" RAM: %u\n\r", raam);
i2c_start();
i2c_write(0x42);
i2c_write(0x4C); //save mode
i2c_stop();
delay_us(130);
}
void readmode(){
int ee;
i2c_start();
i2c_write(0x42);
i2c_write(0x72); //read from EEPROM
delay_us(80);
i2c_write(0x08);//EEPROM address
i2c_stop();
delay_us(80);
i2c_start();
i2c_write(0x43);
ee=i2c_read();
i2c_stop();
printf(" EEPROM: %u\n\r", ee);
}
void main(){
setup_adc_ports (NO_ANALOGS);
setup_adc (ADC_OFF);
setup_spi (SPI_SS_DISABLED);
setup_timer_0 (RTCC_INTERNAL | RTCC_DIV_1);
setup_timer_1 (T1_INTERNAL | T1_DIV_BY_8);
setup_timer_2 (T2_DISABLED, 0, 1);
setup_comparator (NC_NC_NC_NC);
setup_vref (FALSE);
changemode(); //first I change the mode and then i read it
while(true){
readmode();
delay_ms(1000);
}
}
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thanks! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Jan 16, 2009 12:49 pm |
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I didn't look at your code too closely, but I did notice that you're not
giving a NACK on the last read operation. You need to do that.
Add a 0 parameter to i2c_read() statement as shown below:
| Quote: | i2c_start();
i2c_write(0x43);
raam=i2c_read(0);
i2c_stop(); |
There are two places in your code (in total) where this needs to be done. |
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