PPI resources used by S140

[Sverre]

In the documentation for the s140_nrf52_6.0.0 I find the following statement: "The PPI channels and groups that are reserved by the SoftDevice when enabled are defined in
nrf_soc.h.", but when I go into the nrf_soc.h file in my SDK I am not able to find any such information. Could you please supply me with information or guide me to where I can locate it?

And, is it correct that it is not possible to configure the PPI directly when the SoftDevice is present and that all configuration need to be performed through the SD-API defined in nrf_soc.h? At the present we are using the direct assignement through nrf_drv_ppi_channel_assign etc. and do not experience any problems even though we have SD and BLE present and working. My understanding is that the SD should block the access to this peripheral and demand access through its API. Is there something I've missed?

[Håkon Alseth]

Hi,

 

In order to see what PPI channels that are used by the softdevice, you should look at this define:

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s112.api.v6.1.0/group___n_r_f___s_o_c___d_e_f_i_n_e_s.html#ga2274cc200928311ce80bf8c9cc79b990 

The group itself is also defined underneath.

 

The PPI channels from 20 to 31 are the pre-defined ones:

http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52840.ps/ppi.html?cp=2_0_0_5_15_0#preprogrammed_channels

And, is it correct that it is not possible to configure the PPI directly when the SoftDevice is present and that all configuration need to be performed through the SD-API defined in nrf_soc.h? At the present we are using the direct assignement through nrf_drv_ppi_channel_assign etc. and do not experience any problems even though we have SD and BLE present and working. My understanding is that the SD should block the access to this peripheral and demand access through its API. Is there something I've missed?

 The PPI peripheral can be configured directly in the application. In the very first versions of the SoftDevice (for nRF51 series), there was an API for using the PPI, but now you can access it directly on a register level.

If you try to access (ie: write) to a peripheral which the softdevice controls, like the radio, it will cause a fault condition.

 

Kind regards,

Håkon