RAM related issue / What are the best practices (armgcc, linker) > nRF51 16 kB vs 32 kB

RE: RAM related issue / What are the best practices (armgcc, linker) > nRF51 16 kB vs 32 kB

Turbo J — Fri, 28 Apr 2017 18:15:38 GMT

I've used NRF51 with 16k RAM, it should work with in your case. You can try to slim down the softdevice RAM usage by only enabling the minimum amount of stuff.

Note that Segger RTT and NRF_LOG can be a memory hogs, especially when using DEFERRED mode. One could try to minimize buffer sizes here - but more messages would be lost.

Note that hid profile has the side effect that any computer or mobile device will keep the connection active once pairing/bonding is complete. Also, the connection interval on both windows and IOS is lower, resulting in higher data rates - but higher current consumtion, too.

RE: RAM related issue / What are the best practices (armgcc, linker) > nRF51 16 kB vs 32 kB

Johannes Lorenz — Fri, 28 Apr 2017 12:53:16 GMT

Hi, I squeezed a program onto a nRF51 with 16kB RAM, which uses the following components: Softdevice, which takes around 8kB, UART/NUS, DFU, OTA, Libfix math and LIS2/3 DH libraries. I am close to the edge, but it fitted into. As programming environment I use, eclipse, arm gcc and openocd. HTH Johannes

RE: RAM related issue / What are the best practices (armgcc, linker) > nRF51 16 kB vs 32 kB

Jonathan — Fri, 28 Apr 2017 12:46:26 GMT

I'm quite a beginner in embedded (with a past doing low level stuff on PC, though) so pardon me if I'm wrong. Regarding this RAM adjustment you're talking about, I think you always want to use the full RAM (or... there's not reason not to use it), however how RAM will be free depends on the SD configuration (bondings...). Thus, the sd_check_ram_start() function and CHECK_RAM_START_ADDR macro will help you determine how much RAM the softdevice needs, and the rest is yours.