nrf52832 I2C easyDMA

[xueliuhui]

Hello!

I want to use easyDMA. The SDK version  I use is  SDK15.0.I want to know how to config easyDMA.For example , If I only need to config TWI0_USE_EASY_DMA==1  ?

[Simon]

Yes, correct. Let me explain.

When using one of the provided examples in SDK 15 (for example twi_sensor), you have two choices when using I2C: TWIM (also TWIS) or TWI, where the first uses easyDMA and the second does not. When you enable easyDMA through either TWI0_USE_EASY_DMA or TWI1_USE_EASY_DMA, the example will use the functions in the TWIM driver (not the TWI driver).

Best regards, Simon

[asmita_patil]

how to enable twim0...i changed in sdk_config.h still not working..

it was no problem in twi_sensor example...now i am integrating twi_sensor in ble_eddystone...and on built it give an error of "'NRF_DRV_TWI_INSTANCE_0' undeclared here (not in a function); did you mean 'NRF_DRV_TWI_INSTANCE_'?"

what is the reason and can you tell me how to enable twim0..

below is nrf_drv_twi.h file ...which shows that twim0 is not enabled..can you solve yhis problem..it would be great help..thank you.

 

[Simon]

If you look at the file nRF5_SDK_15.3.0\integration\nrfx\legacy\nrf_drv_twi.h, you will see that NRF_DRV_TWI_INSTANCE_0 depends on either NRFX_TWIM0_ENABLED or NRFX_TWI0_ENABLED.

#if NRFX_CHECK(NRFX_TWIM0_ENABLED)
    #define NRF_DRV_TWI_INSTANCE_0 \
        { 0, { .twim = NRFX_TWIM_INSTANCE(0) }, true }
#elif NRFX_CHECK(NRFX_TWI0_ENABLED)
    #define NRF_DRV_TWI_INSTANCE_0 \
        { 0, { .twi = NRFX_TWI_INSTANCE(0) }, false }
#endif
#if NRFX_CHECK(NRFX_TWIM1_ENABLED)
    #define NRF_DRV_TWI_INSTANCE_1 \
        { 1, { .twim = NRFX_TWIM_INSTANCE(1) }, true }
#elif NRFX_CHECK(NRFX_TWI1_ENABLED)
    #define NRF_DRV_TWI_INSTANCE_1 \
        { 1, { .twi = NRFX_TWI_INSTANCE(1) }, false }
#endif

Take a look at nRF5_SDK_15.3.0\integration\nrfx\legacy\apply_old_config.h to see how to enable these two configs. E.g. if you set TWI0_ENABLED and TWI0_USE_EASY_DMA to 1 in the sdk_config.h, then NRFX_TWIM0_ENABLED will be set to 1.

#if defined(TWI_PRESENT) && !defined(TWIM_PRESENT)

#undef NRFX_TWI0_ENABLED
#define NRFX_TWI0_ENABLED   TWI0_ENABLED
#undef NRFX_TWIM0_ENABLED
#define NRFX_TWIM0_ENABLED  0

#undef NRFX_TWI1_ENABLED
#define NRFX_TWI1_ENABLED   TWI1_ENABLED
#undef NRFX_TWIM1_ENABLED
#define NRFX_TWIM1_ENABLED  0

#elif !defined(TWI_PRESENT) && defined(TWIM_PRESENT)

#undef NRFX_TWI0_ENABLED
#define NRFX_TWI0_ENABLED   0
#undef NRFX_TWIM0_ENABLED
#define NRFX_TWIM0_ENABLED  TWI0_ENABLED

#undef NRFX_TWI1_ENABLED
#define NRFX_TWI1_ENABLED   0
#undef NRFX_TWIM1_ENABLED
#define NRFX_TWIM1_ENABLED  TWI1_ENABLED

#else // -> defined(TWI_PRESENT) && defined(TWIM_PRESENT)

#undef NRFX_TWI0_ENABLED
#define NRFX_TWI0_ENABLED   (TWI0_ENABLED && !TWI0_USE_EASY_DMA)
#undef NRFX_TWIM0_ENABLED
#define NRFX_TWIM0_ENABLED  (TWI0_ENABLED && TWI0_USE_EASY_DMA)

Best regards,

Simon