15-Dec.2017 Ver.1.4
TAIYO YUDEN CO., LTD.
TAIYO YUDEN CO., LTD.
8/9
EBSGJN, EKSGJN
EBAGJN, EKAGJN
Important notes
The evaluation board included with the Nordic Development Kit uses a 16MHz clock. Therefore the
sample code from Nordic is designed to be used with a 16MHz clock. On the other hand, the
EYSGJN and EYAGJN series module uses a 32MHz system clock, making it incompatible with the
Nordic sample code (i.e. sample code does not configure HFCLK: XTALFREQ register for
32MHz
).
To fix this issue, we need to write the value 0xFFFFFF00 to the UICR (User Information
Configuration Register) at address 0x10001008. Please note that the UICR is erased whenever you
download a SoftDevice.
The UICR can be written by using the debug tools:
nrfjprog.exe --snr <your_jlink_debugger_serial_number> --memwr 0x10001008 --val 0xFFFFFF00
Or the following code can be added to the SystemInit function in the system_nRF51.c file, right
before launching the TASK_HFCLKSTART task:
if (*(uint32_t *)0x10001008 == 0xFFFFFFFF)
{
NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos;
while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}
*(uint32_t *)0x10001008 = 0xFFFFFF00;
NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos;
while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}
NVIC_SystemReset();
while (true){}
}
32kHz Clock
This module does not installed 32.768kHz crystal. In case of operating without external crystal,
please use following example code in order to enable internal 32.768kHz RC oscillator (32k
RCOSC).
SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_RC_250_PPM_250MS_CALIBRATION, false);
Note that when you choose to use the RC oscillator, it will add around 10uA average current
consumption compared to a 20ppm external crystal.
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