LPC5410x i2c read from register

gossamer69 — Sun, 04 Sep 2016 16:58:21 GMT

I have problems trying to read specific register from i2c device. First I transmit address and register to request reading from device, but when I try to send start (repeated start) it still expects new TX data.. I am not sure what should I send to specify I want to read now...

This is the sample code I am trying to use:

if (!waitForState(MasterStates::Idle)) return false;

m_peripheral->MSTDAT = m_address; //send address of slave and set start

m_peripheral->MSTCTL = MSTSTART;

if (!waitForState(MasterStates::TxRdy)) return false;

m_peripheral->MSTDAT = a_reg; // send address of register i want to read and send continue

m_peripheral->MSTCTL = MSTCONTINUE;

if (!waitForState(MasterStates::TxRdy)) return false;

m_peripheral->MSTDAT = m_address | 1; //set read flag on address and send start (i hoped it would be repeated start)

m_peripheral->MSTCTL = MSTSTART;

if (!waitForState(MasterStates::RxRdy)) return false; //<<<<<<--- this is where I still get TxRdy instead of RxRdy

tmp = m_peripheral->MSTDAT;

m_peripheral->MSTCTL = MSTSTOP;

if (!waitForState(MasterStates::Idle)) return false;

So what should I set after sending the address of register i want to read ?

Thanks

Re: LPC5410x i2c read from register

Hui_Ma — Fri, 09 Sep 2016 06:58:07 GMT

The LPCOpen software for LPC5410x chip provides the I2C master demo, which located at below folder:

..\lpc5410x_lpcxpresso_54102_keil_iar_3.01.000_9\lpc5410x\prj_lpcxpresso_54102\iar

There shows how to use read data from 3-axis accelerometer (Bosch BMC150) with I2C bus.

Wish it helps.

Have a great day,
Ma Hui
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LPC5410x i2c read from register

Re: LPC5410x i2c read from register