What is the FPROTECT block size of nRF5340 Network Core Flash ?

[Ligo George]

In the datasheet I can see that flash memory space is divided in to 64 regions of 16KiB. Which is for application core, (64 * 64 KB = 1MB)

I couldn't find any reference of network core flash protect size in datasheet. Since SPU can have 64 regions, will that be 4KB (64 * 4 KB = 256 KB).

But confusingly I found that by default in code (auto generated autoconf.h), network core uses flash protect size of 2KB (0x800)

#define CONFIG_FPROTECT_BLOCK_SIZE 0x800

[Maria Gilje]

Hello,

The nRF5340 network core does not have a SPU peripheral, see the Instantiation table for the network core here. To find how the default value for CONFIG_FPROTECT_BLOCK_SIZE is set, please see the definition for CONFIG_FPROTECT_BLOCK_SIZE in ncs/nrf/lib/fprotect/Kconfig. There you can see that the last default value is based on a devicetree property. This will be the default value for CONFIG_FPROTECT_BLOCK_SIZE for the nRF5340 network core, because none of the other defaults is applicable for the network core. See the nrf53 Kconfig for reference. The erase-block-size property gets its value in ncs/zephyr/dts/arm/nordic/nrf5340_cpunet.dtsi and has the decimal value 2048 (0x800).

Best regards,

Maria