why data can not be wrote into the registers of nRF52840

[nicholasldf]

hello, nordic's engineers, need your help.

  (1) the first problem : can not set VDD output to 3.3V
  From nRF52840_Product_Specification_v0.5, it says:
  High voltage mode is entered when the supply voltage is only connected 

to the VDDH pin and the VDD pin is not connected to any voltage supply. In high voltage mode, the output from REG0 can be used for supplying external circuitry from the VDD pin.

  Our nRF52840  is using  High voltage mode, so nRF52840 is powered by VDDH pin,  

and voltage of VDDH is 5V; Then we set REGOUT0 and EXTSUPPLY like following

  NRF_UICR->REGOUT0 = 5;//3.3V
  NRF_UICR->EXTSUPPLY = 1;//enable
    
  but the output of VDD pin is still 1.8V， why?


  (2)the second problem  :  can't set radio tx power
  we want increase radio tx power, but it seems that the setting does not 

take effect

  source code :  sd_ble_gap_tx_power_set(8);
  

  (3) add debug source code to read back register value, and print:
           NRF_LOG_INFO("NRF_UICR->REGOUT0 %d\r\n", NRF_UICR->REGOUT0);
       NRF_LOG_INFO("NRF_UICR->EXTSUPPLY %d\r\n", NRF_UICR->EXTSUPPLY);
       NRF_LOG_INFO("NRF_RADIO->TXPOWER %d\r\n", NRF_RADIO->TXPOWER);

  debug onformation got form terminal:
        APP:INFO: NRF_UICR->REGOUT0 -1
        APP:INFO: NRF_UICR->EXTSUPPLY -1
        APP:INFO: NRF_RADIO->TXPOWER 0

  oh, my god, The setting data is not written in , why? why? why?

  very strange :
  NRF_UICR->REGOUT0 and NRF_UICR->EXTSUPPLY are 

always -1(default value when power on), NRF_RADIO->TXPOWER is 0(default value when power on) at most of time , but some times is 8(our setting value).

  debug information printed to UART:
        APP:INFO: NRF_UICR->REGOUT0 -1
        APP:INFO: NRF_UICR->EXTSUPPLY -1
        APP:INFO: NRF_RADIO->TXPOWER 8
        APP:INFO: NRF_UICR->REGOUT0 -1
        APP:INFO: NRF_UICR->EXTSUPPLY -1
        APP:INFO: NRF_RADIO->TXPOWER 0
        APP:INFO: NRF_UICR->REGOUT0 -1
        APP:INFO:NRF_UICR->EXTSUPPLY -1
        APP:INFO:NRF_RADIO->TXPOWER 0

  
  thank you very much!

[butch]

Are the UICR registers non-volatile, i.e. FLASH i.e. a simple assignment does not work?

[Turbo J]

Yes, UICR is NVM and must be treated similar to flash.

[nicholasldf]

butch and Turbo J , thank you.

if UICR are non-volatile, so how to modify its registers ? also, why sd_ble_gap_tx_power_set(8) don't take effect?

[butch]

I think you should read the Nordic documents about writing NV memory, and if you have problems, ask another question. Re tx power, my guess would be that the SoftDevice keeps its own memo about what tx power you have asked for, and sets the radio register TXPOWER dynamically, i.e. on the fly, and restores it to the default after every radio operation. Maybe there is a 'getter' function in the SD API that you can call to inquire what tx power is set. In other words, ask the SD instead of reading the radio register directly.

[nicholasldf]

thank you, butch.

(1) for UICR, page 22 of <S132_SoftDevice_Specification_v3.1.pdf> says:

Access to UICR is Restricted when SoftDevice enabled.

(2) for tx power:

devzone.nordicsemi.com/.../

There isn't any way to get the current TX power level from the stack, so if you need it you have to keep track of it in your application, based on your calls to sd_ble_gap_tx_power_set().

from this post , nordic's engineers says there is no way to read tx-power, because sd_ble_gap_tx_power_get() function is not exist.

devzone.nordicsemi.com/.../

The softdevice will not adjust TX power automatically while running. You can set the TX power level used by calling the function sd_ble_gap_tx_power_set(), or get the current level with the corresponding sd_ble_gap_tx_power_get() function. These functions can be called at any time as long as the softdevice is enabled.

from this post , nordic's engineers says softdevice will not adjust TX power automatically.