Reading from HMC5883L using I2C

RE: Reading from HMC5883L using I2C

bjorn-spockeli — Thu, 22 Jun 2017 19:31:23 GMT

@omart: Please create a new question where you post your code and describe what behavior you're seeing in detail.

RE: Reading from HMC5883L using I2C

omar — Tue, 20 Jun 2017 09:47:24 GMT

Hi, i testes your code source with GY-87 (mpu6050,hmc5883L) and nrf52832 , i activated the bypasse but no data received, how did u resolve the problem !

RE: Reading from HMC5883L using I2C

bjorn-spockeli — Tue, 12 Jul 2016 12:42:35 GMT

Happy to help!

RE: Reading from HMC5883L using I2C

LJohn — Tue, 12 Jul 2016 12:40:28 GMT

Thank you, that worked. I got confused by the way the datasheet explains write/read operations.

RE: Reading from HMC5883L using I2C

bjorn-spockeli — Tue, 12 Jul 2016 08:28:36 GMT

The I2C address of the HMC5833l should not be in the transmit buffers, it's already given as an argument to nrf_drv_twi_tx. So the transmit buffers should look like this:

uint8_t reg[2] = { HMC5883L_REG_CONF_A, 0x70};
uint8_t reg1[2] = { HMC5883L_REG_CONF_B, 0xA0};
uint8_t reg2[2] = { HMC5883L_REG_MODE, 0x00}; 

uint8_t reg3[1] = {HMC5883L_REG_X_MSB };

The data registers ( 0x03 - 0x8) are read-only, so it makes no sense to write to these registers, so the last nrf_drv_twi_tx call and reg4 can be removed.

Bjørn

RE: Reading from HMC5883L using I2C

LJohn — Tue, 12 Jul 2016 08:14:50 GMT

Yes, indeed, sorry for the confusion. However, this merely affects the labeling of probes.

RE: Reading from HMC5883L using I2C

Justin — Mon, 11 Jul 2016 20:54:24 GMT

It looks like you have the logic analyzer setup to SPI where the device and code is using TWI/I2C