Does nRF52820 support multiperipheral？

[helen]

Hi Nordic,

        One of my custmer want to develop multiperipheral product(The device connect to two central devcie).

        The nRF52832 can certainly meet their requirements, and we want to know whether nRF52820 also does.

        1、 I think the main limitation is RAM, I have seen the routine in ......\nRF5_SDK_17.0.2\examples\ble_peripheral\experimental\ble_app_multiperipheral\pca10040. Without any adjustment,  the output need 32.4K RAM, which is lager than 32K of nRF52840

        So I think 52820 may not support multiperipheral application, is this right?

        2、 Accouding to this thought, I found that the output of 'ble_app_uart' need 31.6K RAM, which is qtite close to 32K, if we add some logic, easily it will exceed 32k.

        And  some nRF52 series has 24K RAM, like 52810, 52811, 52805, It means that they can't run the uart routine? I think of crouse they can.

        The key factor maybe we can reduce the RAM of the routine by take out some function like log and so on.

        May you be kindly give some advice on how to reduce the RAM?

[Amanda Hsieh]

Hi Helen, 

Which SD would you use for nRF52820? nRF52820 supports s112, s113 and s140. In those, only S140 can support concurrent connections.

It also needs to reserve the RAM for the Softdevice. For example, the minimum required memory of 140 v7.2.0 is 5.6 kB (0x1678 bytes). The actual requirements depend on the configuration chosen at sd_ble_enable() time. Check the s140_nrf52_7.2.0_release-notes.pdf under nRF5_SDK_17.0.2_d674dde\components\softdevice\s140\doc

You could try compiling with size optimizations, disable logging, remove some features, etc. If you still can't reduce the application size, you would consider an SoC variant with larger flash.

Regard, 
Amanda

[helen]

Hi Amanda,

You could try compiling with size optimizations, disable logging, remove some features, etc.

For the "ble_app_uart",what feature may I remove to reserve RAM?

[Amanda Hsieh]

Hi Helen, 

You can use ble_app_uart_pca10100e_s140 for nRF52820. It can fit the RAM size without removing features. 

-Amanda