I2C Detection Fail

[coder_72]

Hello everyone,

I have a problem with the OM40001 sample "lpcxpresso804_lpc_i2c_interrupt_b2b_transfer_slave". I have removed the bridges for the LM75 and agreed on a slave on SCL PIO0_14 and SDA PIO0_7. I can't find the device on my agreed address with an I2C detect with an I2C master. I have connected SCL with SCL and SDA with SDA.
Does anyone have a solution? Thanks a lot.

[xiangjun_rong]

Hi,

I have downloaded the data sheet of LM75, which is a temperature sensor with I2C interface, but the LPC75 can only be a I2C slave in stead of master, if you use the I2C module of LPC804 with SCL PIO0_14 and SDA PIO0_7, the I2C module of LPC804 is master.

For the device address of LM75, it has A2/A1/A0 pins, this is address format.

Assume that the A2/A1/A0 pin logic is 000 via pull up/down resistors, the I2C device address of LM75 is 0x48. Assume that the A2/A1/A0 pin logic is 011, the I2C device address of LM75 is 0x4B.

Because the I2C of LPC804 is master, so you have to use the

Hope it can help you

BR

XiangJun Rong