Hello: I want to add some code that enables the DC/DC regulator for the nordic chips. Enabling this regulator reduces power consumption (considerably). For example, using the LDO when running from flash (cache enabled) is typically 7.4mA; using the DC/DC regulator it goes to 3.7 mA.
It would be best to turn this on as soon as possible but it should only be enabled if there is some external circuitry attached to some of the pins (see the product specifications for more details). For all the BSP’s currently in the repo, the DC/DC regulator can (and should) be enabled. GIven that there is external circuitry involved I was going to create a syscfg variable that would either exist in the BSP or be overridden by the BSP. What I am having a bit of trouble figuring out is where should the code to enable the DC/DC regulator go? We have a choice of putting it in an existing place or doing something new. It seems to me that if we choose an exisiting place it would go in either hal_bsp_init() or hal_system_start(). Some comments about the existing functions: hal_system_start(): * Code would only need to be modified in one place (in hw/mcu). * This function is called after the bootloader does some work, so more power savings could be realized earlier on. * If you build an image with no bootloader I do not think this is called. * It might be a bit of an odd place to put this code (enabled the DC/DC regulator). hal_bsp_init(): * This is called early on by the bootloader. It is also called by the application which is a bit confusing to me. I am not super familiar with the bootloader but unless this function exists in some place I do not see or we override bsp syscfg variables in the bootloader app, hal_bsp_init() is going to do things twice. Is this true or am I missing something? * We would have to modify hal_bsp_init() in all the bsps. Honestly, I am not too concerned about having to modify all the bsps that use the nordic chip if the community thinks this code belongs in hal_bsp_init(). Any comments/suggestions? Thanks! PS If we decide that this code should exist in hw/mcu what I would do is to create a syscfg variable in hw/mcu/nordic (or hw/mcu/nordic/nrf52xxx and hw/mcu/nordic/nrf51xxx) called MCU_DCDC_ENABLE (or some such). By default, this will be 0. All the bsp syscfg.yml files will override this setting.
