TWI Switch between easyDMA and normal read

[Constantin]

Hi,

I am reading a BMX055 via I2C which consists of three sensors with three addresses. I got the easyDMA running to read 10 times the gyro using the PPI and the data ready interrupt. Now after 10 readings I want to read once the accelerometer and the magnetometer. But if I try to read with

nrf_drv_twi_tx(&m_twi_instance, address, &reg, 1, false); nrf_drv_twi_rx(&m_twi_instance, address, p_data, length);

I get the NRF_ERROR_BUSY which means that the TWIM is still in use. So here is my question how can I switch from easyDMA reading to normal reading.

Thanks and kind regards,

C.

[Jørgen Holmefjord]

Do you setup the TWIM transfers using the TWI driver as well? The error code NRF_ERROR_BUSY will only be returned if the driver is busy, it will not check the state of the peripheral. Did the error code come from nrf_drv_twi_tx or nrf_drv_twi_rx call? Note that unless you initialize the driver in blocking mode, you need to make sure the first transfer is finished before calling the receive function.

[timsterc]

Wondering if you were ever able to make this work?

I'm working from the https://github.com/Martinsbl/nrf5-mpu-examples/tree/sdk13/nrf52-mpu-easydma-using-gpiote-and-registers example and the DMA portion is working splendidly, but I also need to be able to put the MPU into a sleep mode, where it can wakeup the nRF52 on motion. This has all worked fine in the past, but I'm struggling to figure out what specifically I need to do to 'undo' the DMA setup, and get back to 'normal' (non-DMA) comms w/ the MPU.

[Jørgen Holmefjord]

I would recommend that you create a new support request with details on your issue. This way we can help you without this thread becoming too large.