Firmware Flow

ElemRV platforms support two firmware flows: a bare-metal flow for low-level applications without an RTOS, and a Zephyr flow for applications built on top of the Zephyr RTOS. Both flows produce an image container that is flashed onto the SPI flash of the target hardware.

The SOC variable selects the platform (default: ElemRV-N) and the board variable selects the target process node (default: SG13G2).

Bare-Metal

The bare-metal flow compiles two applications:

• bootrom - minimal startup code that initialises the CPU and hands off to the application in flash.

• demo - a bare-metal demonstration application showcasing the platform peripherals.

Both are compiled and packed into baremetal_container.img.

Compile

task baremetal:compile

To target a specific platform:

task baremetal:compile SOC=ElemRV-N board=SG13G2

The compiled image is written to:

build/<SOC>/<board>/firmware/baremetal_container.img

Zephyr

The Zephyr flow compiles the bootrom alongside a Zephyr application and packs them into zephyr_container.img.

Compile

task zephyr:compile

To target a specific platform:

task zephyr:compile SOC=ElemRV-N board=SG13G2

The compiled image is written to:

build/<SOC>/<board>/firmware/zephyr_container.img

Flash Layout

The SPI flash is partitioned as defined in software/<platform>/spi.layout. For ElemRV-N the layout is:

00000000:0001ffff flash

The image container is written into the flash region starting at address 0x00000000.

Flash

Programs the SPI flash using flashrom over a Bus Pirate 5 at 8 MHz. The target flash chip is a Micron MT25QL256.

For bare-metal:

task baremetal:flash

For Zephyr:

task zephyr:flash

Note

The flash task expects the Bus Pirate 5 to be connected and enumerated at /dev/serial/by-id/usb-Bus_Pirate_Bus_Pirate_5_5buspirate-if02. Adjust the device path in the respective Taskfile if your setup differs.