2e7f75f6e0
Chip name : rp23xx-rv Board name : raspberrypi-pico-2-rv Arch : risc-v Changes from ARM rp23xx impl - Linker script update - ASM head start - Update chip start - New Hazard3 registers - Remove rp23xx chip hw spinlocks/testset - New irq handling (external IRQ interrupt Hazard3) - New timerisr based on RISC-V std MTIME and alarm arch - No SMP yet - Tickless option - Double size for idle, irq and main stacks - Board reset via watchdog trigger Signed-off-by: Serg Podtynnyi <serg@podtynnyi.com>
219 lines
6.9 KiB
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219 lines
6.9 KiB
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=========================
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RaspberryPi rp2350 RISC-V
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=========================
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.. tags:: chip:rp2350
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The rp2350 is a dual core chip produced by the RaspberryPi Foundation that
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is based on ARM Cortex-M33 or the Hazard3 RISC-V.
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ARM Cortex-M33 and Hazard3 RISC-V cores are supported.
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This is RISC-V version of the chip configuration.
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This port is experimental and still a work in progress. Use with caution.
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SMP (dual core configuration not supported yet)
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Peripheral Support
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==================
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Most drivers were copied from the rp2040 port with some modifications.
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The following list indicates peripherals currently supported in NuttX:
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============== ============ =====
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Peripheral Status Notes
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============== ============ =====
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GPIO Working See Supported Boards documentation for available pins.
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UART Working GPIO 0 (UART0 TX) and GPIO 1 (UART0 RX) are used for the console.
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I2C Working
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SPI Master Working
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SPI Slave Untested
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DMAC Working
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PWM Working
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USB Working
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PIO Working
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IRQs Working
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WDOG Working
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DMA Working
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FPU/DSP INOP Available in ARM configuration of the chip
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Clock Output Untested
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Flash ROM Boot Working Does not require boot2 from pico-sdk
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If picotool is available a nuttx.uf2 file will be created
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SRAM Boot Working Requires external SWD debugger
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PSRAM Working Three modes of heap allocation described below
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============== ============ =====
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Installation
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============
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1. Download and build picotool, make it available in the PATH::
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git clone https://github.com/raspberrypi/picotool.git picotool
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cd picotool
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mkdir build
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cd build
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cmake ..
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make
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cp picotool ~/local/bin # somewhere in your PATH
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2. Download NuttX and the companion applications. These must both be
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contained in the same directory::
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git clone https://github.com/apache/nuttx.git nuttx
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git clone https://github.com/apache/nuttx-apps.git apps
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3. Download and install RISC-V compatible toolchain
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with arch `rv32imac` and `ilp32` abi.
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https://xpack-dev-tools.github.io/riscv-none-elf-gcc-xpack/
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Building NuttX
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==============
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1. Change to NuttX directory::
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cd nuttx
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2. Select a configuration. The available configurations
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can be listed with the command::
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./tools/configure.sh -L
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3. Load the selected configuration.::
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make distclean
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./tools/configure.sh raspberrypi-pico-2-rv:usbnsh
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4. Modify the configuration as needed (optional)::
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make menuconfig
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5. Build NuttX::
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make
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Flash boot
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==========
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By default, the system is built to build and run from the flash
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using XIP. By using the default `BOOT_RUNFROMFLASH` configuration,
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the full image is run from the flash making most of the internal
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SRAM available for the OS and applications, however the execution
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is slower. The cache can speed up, but you might want set your
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time critical functions to be placed in the SRAM (copied from
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the flash on startup).
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It is also possible to execute from SRAM, which reduces the
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available SRAM to the OS and applications, however it is very
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useful when debugging as erasing and rewriting the flash on
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every build is tedious and slow. This option is enabled with
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`BOOT_RUNFROMISRAM` and requires `openocd`` and/or `gdb`.
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There is a third option which is to write the firmware on the
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flash and it gets copied to the SRAM. This is enabled with
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`CONFIG_BOOT_COPYTORAM` and might be useful for time critical
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applications, on the expense of reduced usable internal SRAM
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memory.
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PSRAM
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=====
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Some boards like the `pimoroni-pico-2-plus` have a PSRAM
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which greatly increases the available memory for applications.
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The PSRAM is very slow compared to the internal SRAM,
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so depending on the application, different configuration might
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be necessary.
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To use the PSRAM, enable the `RP23XX_PSRAM` and select the GPIO
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pin used as CS1n with `RP23XX_PSRAM_CS1_GPIO`. See the RP2350
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datasheet for more information.
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The port offers three options for configuring the heaps to use
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the external PSRAM, described below. More custom configurations
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can be used with custom board initialization functions.
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Use PSRAM and SRAM as a single main heap
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----------------------------------------
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This option is selected with `RP23XX_PSRAM_HEAP_SINGLE` and
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requires `MM_REGIONS > 1`, as the PSRAM memory region will
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be added to the heap. It is also necessary to disable
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`MM_KERNEL_HEAP`, as there will only be a single heap.
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This is the simplest configuration because it will unify the
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memories into a single main heap. This way you can see the `free`
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command output the total amount of usable RAM in the heap.
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However, there are some unpredictable performance issues because
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there is no control of where the memory is allocated when issuing
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`malloc(3)` and `free(3)`. For this reason, you might want to
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consider the other options.
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Use PSRAM as user heap, SRAM as kernel heap
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-------------------------------------------
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This option is selected with `RP23XX_PSRAM_HEAP_USER` and
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requires `MM_KERNEL_HEAP` to be set.
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The external PSRAM is allocated to the default heap, while
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the internal SRAM will be used for the kernel heap. This
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configuration is useful because it allows drivers to
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use the SRAM and behave much faster than if they used
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memory on the PSRAM. While user applications can take
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the bull benefit of the larger slower heap on the PSRAM.
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Use PSRAM as a separate heap
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----------------------------
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This option is selected with `RP23XX_PSRAM_HEAP_SEPARATE` and
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requires `ARCH_HAVE_EXTRA_HEAPS` to be set.
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The internal SRAM is used as the main heap for kernel and
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applications, as if there was no PSRAM configured. The
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external PSRAM is configured as a separate user heap called
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`psram` and can be used through the global variable
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`g_psramheap` after including `rp23xx_heaps.h`
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Programming
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============
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Programming using BOOTSEL
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-------------------------
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Connect board to USB port while holding BOOTSEL.
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The board will be detected as USB Mass Storage Device.
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Then copy "nuttx.uf2" into the device.
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(Same manner as the standard Pico SDK applications installation.)
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Programming with picotool
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-------------------------
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You can use picotool to load the elf (or the uf2)::
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picotool load nuttx -t elf
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Programming using SWD debugger
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------------------------------
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Most boards provide a serial (SWD) debug port.
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The "nuttx" ELF file can be uploaded with an appropriate SDB programmer
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module and companion software (openocd and gdb)
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Running NuttX
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=============
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Most builds provide access to the console via UART0. To access this
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GPIO 0 and 1 pins must be connected to the device such as USB-serial converter.
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The `usbnsh` configuration provides the console access by USB CDC/ACM serial
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device. The console is available by using a terminal software on the USB host.
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Supported Boards
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================
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.. toctree::
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:glob:
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:maxdepth: 1
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boards/*/*
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