Accessing the nrf52820 pins

[MuRa]

Hello all

I am porting the code from the nRF52DK to the nrf52820, and so far so good, however, I am having a question, when configuring the TWI, will this get me the right PINS, for instance, according to the module manufacturer I should be accessing the P0.02 for SDA, while P0.08 for the SCL , this is my code:

void twi_init (void)
{
    ret_code_t err_code;

    const nrf_drv_twi_config_t twi_config = {
       .scl                = NRF_GPIO_PIN_MAP(0, 8), // ARDUINO_SCL_PIN,   //Add you SCL Pin Here
       .sda                = NRF_GPIO_PIN_MAP(0, 2), // ARDUINO_SDA_PIN,   //Add you SDA Pin Here
       .frequency          = NRF_DRV_TWI_FREQ_100K,
       .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
       .clear_bus_init     = false
    };

    err_code = nrf_drv_twi_init(&m_twi, &twi_config, twi_handler, NULL);
    APP_ERROR_CHECK(err_code);

    nrf_drv_twi_enable(&m_twi);
}

This part works on the nrf52dk, for example where I am directly using the P0.27 and P0.26, however, the numbers 26 and 27 are simply used, as 26 and 27... 

hence my question, if I am accessing the pins correctly?

best.

[MuRa]

True that, I am looking at the el. schematics, ok, for example, how can someone enable or use the pin P0.20?

for example, I have tried to toggle the P0.14 with the nrf_gpio_pin_write(14, 1); //P(0.14)   / nrf_gpio_pin_clear(14); the led, so, now I would like to do the same with the P0.20?

Further more, I am trying to reach the pin F3, have a look at the attached pic, but not sure what M P stands for? 

Was hopping that the GPIO could be assigned via software ...

BEST. 

[nRF5xFanboy]

Hi MuRa,

Sorry for the late feedback (i had a long ad hoc meeting ;-)

mmh this electronic drawing is not very clear in the pin naming (it's a good puzzle)
You just need to hunt all the chip's proper datahseets and collect all the information.

1st question about the twi_config / pins

Looking at the PAN1781 product datahseet
nl.mouser.com/.../IntegrationGuideRFModulePAN1781Series052421.pdf
On page 10 you will see the pins identifiers C4 & C5 (not handy labels for software people ;-)

if you search the labels in the WM PAN1781 Product Specification.pdf  
https://mediap.industry.panasonic.eu/assets/custom-upload/Devices/Wireless%20Connectivity/Bluetooth%20Low%20Energy%20Modules/PAN1781/WM%20PAN1781%20Product%20Specification.pdf

On page 11  you will find:
C4 = SWDIO , Digital BI,  Serial Wire Data I/O
C5 = SWDCLK, Digital IN,  Serial Wire Data Clock

I only do not see any official TWI (i2c) pins coming out of the microcontroller / PAN1781 module.
I only see the SWDCLK & SWDIO.
As you can see in the datasheet of the Nordic nrf52820 https://infocenter.nordicsemi.com/pdf/nRF52820_OPS_v0.7.pdf.
It tells you that it is impossble to use theese pins as a normal TWI pins?
More information on the control access port (for the debug access port) is on page 43

unclear what you want with the TWI on the pan1781 route to the swd pins?

2nd question  "I have tried to toggle the P0.14 ....   now I would like to do the same with the P0.20?"
The the answer is simple 
nrf_gpio_pin_write(12, 1); // to make the gpio  level high (assume positive signal level.)
nrf_gpio_pin_write(12, 0); // to make the gpio  level low 

3rd question: "reach the pin F3"
The names are copied from the FT232R chip datasheet (https://nl.mouser.com/datasheet/2/163/DS_FT232R-11534.pdf see page 7)
The USB D- wire is called at the FT232RQ -> pin no. 15 USB Data Signal Plus
The USB D+ wire is called at the FT232RQ -> pin no. 16 USB Data Signal Minus 

The 'M' perhaps indicate the PAN1781 is a bus-Master (or MCU) on this interface?
I am not sure, my advise, just try to follow the interfacing as is described in the FT232R chip datasheet.

Thanks for the nice puzzle

Hope my answers do help you, have a nice day.

Kind regards,
        nRF5xFanBoy