How to change the internal capacity of XOSC32MCAPS

RE: How to change the internal capacity of XOSC32MCAPS

Bendik Heiskel — Mon, 07 Nov 2022 15:47:24 GMT

Is there any application flashed to the chip?

Try to recover both the network and application cores, and then write to the XOSC32MCAPS register.

The network core must be recovered first using:

nrfjprog --coprocessor CP_NETWORK --recover

And then the application core can be recovered using:

nrfjprog --recover

[quote user="Summer.Xu"]If we want to set the internal capacitors to be 0, which command could use?[/quote]

Do you want to disable the capacitors? Setting the register to 0 will disable them. If you want to set the capacitance to the lowest value you must write 0x100 to the register.

You are using the correct command for writing to the register.

[quote user="Summer.Xu"]And waht is the test step？[/quote]

To test the crystal oscillating frequency its best to use a constant carrier output from the radio and measure the frequency offset using a spectrum analyzer.

To enable a constant carrier at 2.44GHz using nrfjprog you can use these commands in this order:

nrfjprog --coprocessor CP_NETWORK --memwr 0x41008508 --val 40 
nrfjprog --coprocessor CP_NETWORK --memwr 0x4100850C --val 0xFD
nrfjprog --coprocessor CP_NETWORK --memwr 0x41005000 --val 1
nrfjprog --coprocessor CP_NETWORK --memwr 0x41008000 --val 1

Best regards,

Bendik

RE: How to change the internal capacity of XOSC32MCAPS

Summer.Xu — Mon, 07 Nov 2022 10:36:53 GMT

Hi ，

Thanks for your reply.

We just want to use the J-Link tool to modify the capacitors to find the appropriate value . We don't make the power cycle when we do the test.Now I had install the 'nrf-command-line-tools' .If we want to set the internal capacitors to be 0, which command could use? And waht is the test step？

Looking forward the reply~Thanks.

RE: How to change the internal capacity of XOSC32MCAPS

Bendik Heiskel — Fri, 04 Nov 2022 14:45:35 GMT

Hi,

Is the chip being power cycled between the write and read?

If there is FW running on the device it will rewrite the register on boot to the value specified in the FW.

The internal capacitors can be configured in the application using the kconfig options:

CONFIG_SOC_HFXO_CAP_INTERNAL

CONFIG_SOC_HFXO_CAP_INT_VALUE_X2

Best regards,

Bendik