TIWM and GPIO input

[lelisele]

I'm developing an interface I2C to one sensor including SCL, SDA and open-drain return to know if

the sensor is ready to work. After Reset by "Build and Run" form Segger (SDK 16) the TWIM works

very well. But after any read form GPIO input (state of sensor) the TWIM is out service and only new

Download remains TWIM working. I've tried: nrf_gpio_pin_input_get, nrf_gpi_input_read. This Input

was reconfigured as follow:  nrf_gpio_cfg(I2C_SDA2,NRF_GPIO_PIN_DIR_INPUT,NRF_GPIO_PIN_INPUT_CONNECT,
NRF_GPIO_PIN_PULLUP,NRF_GPIO_PIN_S0S1,NRF_GPIO_PIN_NOSENSE); but also nrf_gpio_cfg_input (I2C_SDA2,NRF_GPIO_PIN_PULLUP)

with same bad reaction. Is it  possible that only one GPIO's read is able to block TWIM?????. I've tried : On/off of TWIM, new initialization, On/off of sensor

any way I need always to Re-Download nrf52840 to work with I2C. I'm using nrf52840 development board as Jtag interface to my board. 

[Øyvind]

Hello, 

Have you tried using our TWI examples to verify connection/functionality?

• TWI Scanner Example
• TWI Sensor Example
• TWI Transaction Manager Example
• TWIS Slave and TWI Master Mode Drivers Example

Kind regards,
Øyvind

[lelisele]

Thanks for your quick answer. My TWIM works very well. It is based on the direct access to registers and HAL drivers.

It takes about twenty lines in SW !!!!!!!! to interface my sensor. The problem is when I read one GPIO input (pin 19) the TWIM (pin 21 and 23) is blocked and I need re-download application That is extremely strange.  

[Øyvind]

Have you tried debugging the issue to pinpoint where it fails? Are you getting any error messages?

Kind regards,
Øyvind

[lelisele]

Is blocked on:  while (NRF_TWIM1->EVENTS_STOPPED == 0); I don't understand what one GPIO input reading can change in TWIM periphery?   

[lelisele]

Additionally, after reading input the I2C clock becomes Low even strong PoolUp?

[Øyvind]

Can you please provide your code? I'm not able to see what the issue is.

Thanks!

Kind regards,
Øyvind

[lelisele]

Hi, Thanks for your help.

I2C pins:

nrf_gpio_cfg(GYRO_SCLK2_I2C_SCL1,NRF_GPIO_PIN_DIR_OUTPUT,NRF_GPIO_PIN_INPUT_CONNECT,
NRF_GPIO_PIN_PULLUP,NRF_GPIO_PIN_H0H1,NRF_GPIO_PIN_NOSENSE);

nrf_gpio_cfg(I2C_SDA2,NRF_GPIO_PIN_DIR_INPUT,NRF_GPIO_PIN_INPUT_CONNECT,
NRF_GPIO_PIN_PULLUP,NRF_GPIO_PIN_S0S1,NRF_GPIO_PIN_NOSENSE);

State pin:

 nrf_gpio_cfg_input (ECG_INTB,NRF_GPIO_PIN_PULLUP); 

I2C initiation:

//Pin definition
NRF_TWIM1->PSEL.SCL = GYRO_SCLK2_I2C_SCL1;
NRF_TWIM1->PSEL.SDA = I2C_SDA2;
// TWIM initialisation
NRF_TWIM1->ADDRESS = 94;
NRF_TWIM1->FREQUENCY = TWIM_FREQUENCY_FREQUENCY_K100 << TWIM_FREQUENCY_FREQUENCY_Pos;
NRF_TWIM1->SHORTS = 0;
//TWIN enable
NRF_TWIM1->ENABLE =TWIM_ENABLE_ENABLE_Enabled << TWIM_ENABLE_ENABLE_Pos; // enable

State pin lecture:

ret = nrf_gpio_pin_input_get (ECG_INTB); //read IntB

I2C data:

static uint8_t LastAddressRead;
static uint8_t tx_buf[2]; /**< TX buffer. */
static uint8_t tx_for_rx_buf[1]; /**< TX buffer. */
static uint8_t rx_buf[1]; /**< RX buffer. */

I2C read:

rx_buf[0] = 0; 

NRF_TWIM1->SHORTS = TWIM_SHORTS_LASTTX_STARTRX_Msk | TWIM_SHORTS_LASTRX_STOP_Msk;

tx_for_rx_buf[0] = LastAddressRead;
NRF_TWIM1->TXD.MAXCNT = 1;
NRF_TWIM1->TXD.PTR = (uint32_t)&tx_for_rx_buf[0];

NRF_TWIM1->RXD.MAXCNT = 1;
NRF_TWIM1->RXD.PTR = (uint32_t)&rx_buf[0];

NRF_TWIM1->EVENTS_STOPPED = 0;
NRF_TWIM1->EVENTS_LASTTX = 0;

NRF_TWIM1->TASKS_STARTTX = 1;

 while (NRF_TWIM1->EVENTS_STOPPED == 0);

nrf_delay_us(50);

return (rx_buf[0]);

[Øyvind]

Please add all defines as well, as e.g. I2C_SDA2, etc are not in nRF SDK.