Not able to read analog value from a Proteus III board (nrf52840 SoC)

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

Adarsh_1 — Fri, 23 Oct 2020 07:42:44 GMT

Hi,

Yes it was it. A wrong Pin mapping. The files came along with the product was wrong. Thank you so much. Now it is working as expected.

regards,

Adarsh

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

hmolesworth — Thu, 22 Oct 2020 19:42:59 GMT

This is a bug:

    nrf_saadc_channel_config_t channel_config =
        NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_PIN_BOOT);

See edit above

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

hmolesworth — Thu, 22 Oct 2020 15:49:29 GMT

Edit:

This is a bug:

    nrf_saadc_channel_config_t channel_config =
        NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_PIN_BOOT);

It uses 2 as a parameter, which is AIN1 not AIN0. Change to this:

    nrf_saadc_channel_config_t channel_config =
        NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN0);

See the enum:

#define SAADC_CH_PSELP_PSELP_AnalogInput0 (1UL) /*!< AIN0 */
#define SAADC_CH_PSELP_PSELP_AnalogInput1 (2UL) /*!< AIN1 */

/**
 * @brief Input selection for the analog-to-digital converter.
 */
typedef enum
{
    NRF_SAADC_INPUT_DISABLED = SAADC_CH_PSELP_PSELP_NC,           ///< Not connected.
    NRF_SAADC_INPUT_AIN0     = SAADC_CH_PSELP_PSELP_AnlogInput0, ///< Analog input 0 (AIN0).
    NRF_SAADC_INPUT_AIN1     = SAADC_CH_PSELP_PSELP_AnalogInput1, ///< Analog input 1 (AIN1).
    NRF_SAADC_INPUT_AIN2     = SAADC_CH_PSELP_PSELP_AnalogInput2, ///< Analog input 2 (AIN2).
    NRF_SAADC_INPUT_AIN3     = SAADC_CH_PSELP_PSELP_AnalogInput3, ///< Analog input 3 (AIN3).
    NRF_SAADC_INPUT_AIN4     = SAADC_CH_PSELP_PSELP_AnalogInput4, ///< Analog input 4 (AIN4).
    NRF_SAADC_INPUT_AIN5     = SAADC_CH_PSELP_PSELP_AnalogInput5, ///< Analog input 5 (AIN5).
    NRF_SAADC_INPUT_AIN6     = SAADC_CH_PSELP_PSELP_AnalogInput6, ///< Analog input 6 (AIN6).
    NRF_SAADC_INPUT_AIN7     = SAADC_CH_PSELP_PSELP_AnalogInput7, ///< Analog input 7 (AIN7).
    NRF_SAADC_INPUT_VDD      = SAADC_CH_PSELP_PSELP_VDD           ///< VDD as input.
} nrf_saadc_input_t;

Maybe try some explicit setting in saadc_init() like this (removes the bbug):

    nrf_saadc_channel_config_t channel_config =
        //NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_PIN_BOOT);
    {
        .resistor_p = NRF_SAADC_RESISTOR_DISABLED,
        .resistor_n = NRF_SAADC_RESISTOR_DISABLED,
        .gain       = NRF_SAADC_GAIN1, //1_6,
        .reference  = NRF_SAADC_REFERENCE_INTERNAL,
        .acq_time   = NRF_SAADC_ACQTIME_40US,
        .mode       = NRF_SAADC_MODE_SINGLE_ENDED,
        .burst      = NRF_SAADC_BURST_DISABLED,
        .pin_p      = NRF_SAADC_INPUT_AIN0,
        .pin_n      = NRF_SAADC_INPUT_DISABLED
    };

Edit: Just a thought, is the SoftDevice enabled? If so PPI changes have to use the sd functions:

uint32_t 	sd_ppi_channel_enable_get (uint32_t *p_channel_enable)
 	Get PPI channel enable register contents. More...
 
uint32_t 	sd_ppi_channel_enable_set (uint32_t channel_enable_set_msk)
 	Set PPI channel enable register. More...
 
uint32_t 	sd_ppi_channel_enable_clr (uint32_t channel_enable_clr_msk)
 	Clear PPI channel enable register. More...
 
uint32_t 	sd_ppi_channel_assign (uint8_t channel_num, const volatile void *evt_endpoint, const volatile void *task_endpoint)
 	Assign endpoints to a PPI channel. More...
 
uint32_t 	sd_ppi_group_task_enable (uint8_t group_num)
 	Task to enable a channel group. More...
 
uint32_t 	sd_ppi_group_task_disable (uint8_t group_num)
 	Task to disable a channel group. More...
 
uint32_t 	sd_ppi_group_assign (uint8_t group_num, uint32_t channel_msk)
 	Assign PPI channels to a channel group. More...
 
uint32_t 	sd_ppi_group_get (uint8_t group_num, uint32_t *p_channel_msk)
 	Gets the PPI channels of a channel group. More...

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

Adarsh_1 — Thu, 22 Oct 2020 09:50:58 GMT

Hai Jared,

If you go in the "boards.h" header file which is included in the program, you can see that the custom board ("ProteusIII.h") file is included as you have mentioned above. I have linked the Proteus III hardware instead of BOARD_PCA10056 in PREPROCESSOR -> SET PREPROCESSOR DEFINISION according to this post. Is there a need to add the step you mentioned even after adding the board in the preprocessor?

If so, can you refer some links on how to do it.

I am certain that the compiler is already linked with the board files since I am able to provide digital signals to different pins in the custom board using the same application and header file.

Thank you

regards,

Adarsh

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

Jared — Thu, 22 Oct 2020 07:38:10 GMT

Hi,

I see that you've included the custom board file but where do you tell the application to use that instead of the nRF52840 standard board file?

"To add support for a custom board, you must create a custom board support file with the name custom_board.h. This file must be located in a directory in the Include path. You can then select to use the custom board by adding the define statement #define BOARD_CUSTOM".

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

Adarsh_1 — Wed, 21 Oct 2020 12:34:46 GMT

Hi Jared,

I am using a custom fw but I tried to use the saadc nordic example as well. I will upload the project with nordic saadc example including the confic files and board files. Here I have used 12 bit SAADC and receives an output like this. It does not change its values at all. (Even after applying GND and VDD to the Pin).

Here is the file.

devzone.nordicsemi.com/.../saadc_5F00_Proteus.zip

regards,

Adarsh

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

Jared — Wed, 21 Oct 2020 09:28:35 GMT

Hi,

Are you using an example from the SDK or is it custom fw that you're running? Could you upload your application along with the SDK config file and the custom board file?

regards

Jared

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

Adarsh_1 — Tue, 20 Oct 2020 12:59:41 GMT

Hi Jared,

Thanks for the reply.

All the jumpers on JP2 are connected except for (1,2) and (3,4). This is the default configuration. I am sorry I am not able to upload images and I don't know why. It's weird. But you can find the default configuration table for JP2 on this file. (Page 10, table 6)

There are no jumpers at PI as you can see from the same file. Pin 2 of Pinheader P1 is BOOT pin and is configured as an analog pin in my code.

When I measure directly on pin 2 of Pin header P1, I almost get a very low voltage value (3mV or so). I tried connecting Pin 1(VDD) to Pin 2(AIN) of Pin header P1, measuring a voltage of 2.95V on Pin 2 but still, the value in the serial monitor is not changing.

I thought this might be a hardware issue, but I cannot actually find it out. When I contacted the board manufacturers, they told me that all the Nordic examples are supposed to work on their board provided that I use the internal HFCLK and board header files. Everything works perfectly fine but cannot read analog pins properly. In their firmware, BOOT pin was used for OTA bootloader settings but I have erased the chip completely before flashing the softdevice and firmware. And so this wouldn't be a problem.

I think I am missing out on some important points but I am stuck with this for a couple of days.

Waiting for your reply.

regards,

Adarsh

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

Jared — Tue, 20 Oct 2020 11:50:03 GMT

Hi,

How is the jumper on pin header P1 and JP2 configured? What voltage do you measure if you measure directly on the pin?

btw: This was a very good explanation of your issue, and what steps you've tried to find the root cause.

regards

Jared

RE: Not able to read analog value from a Proteus III board (nrf52840 SoC)

Adarsh_1 — Mon, 19 Oct 2020 14:05:25 GMT

Sorry. I forgot to mention that I am using SDK version 17.02 and softdevice s140_nrf52_7.2.0_API.