Hardware Overview

Microcontrollers

MicrocontrollersCommercial BoardsRP2040SWD Debugging the RP2040STM32F769IDiscoveryPin OutsCN9CN8CN5CN4CN11(Mikrobus)CN3(Grove)CN4ArduinoAzure-RTOS and startup

Commercial Boards

The following is a list of commercial boards that are either ported or planned to be ported to run the nanoFramework

RP2040

The Raspberry Pi Pico is a high-performance microcontroller chip designed by Raspberry Pi in the United Kingdom

The Chip features

• Dual-core Arm Cortex M0+ processor, flexible clock running up to 133 MHz

• 264kB of SRAM, and 2MB of on-board flash memory

• USB 1.1 with device and host support

• Low-power sleep and dormant modes

• Drag-and-drop programming using mass storage over USB

• 26 × multi-function GPIO pins

• 2 × SPI, 2 × I2C, 2 × UART, 3 × 12-bit ADC, 16 × controllable PWM channels

• Accurate clock and timer on-chip

• Temperature sensor

• Accelerated floating-point libraries on-chip

• 8 × Programmable I/O (PIO) state machines for custom peripheral support

SWD Debugging the RP2040

To allowing porting the nanoFramework to the RP2040, a native C/C++ debugging facility is required. ( unless you can write perfect code)

There a couple of ways to do this, the following describes the Picoprobe method.

For the complete description you can find the relevant information in the documentation at Getting started with Raspberry Pi Pico in Chapter 6. Debugging with SWD and the Appendix A: Using Picoprobe.

The complete official Picoprobe source can be found at GITHUB.

At the time of starting the porting of the native C/C++ code for nanoFramework to the RP2040 I had the following two boards, the official Pico board and one from Seeed the XIAO RP2040. I decided to use the Seeed XIAO RP2040 board as the picoprobe which only uses a couple of pins.

After downloading the code from GitHub - raspberrypi/picoprobe, I made some modifications to the picoprobe_config.h file to match the GPIO ports I have chosen to connect to the SWD debugging port.

// PIO config
#define PROBE_SM 0
#define PROBE_PIN_OFFSET 28
#define PROBE_PIN_SWCLK PROBE_PIN_OFFSET + 0
#define PROBE_PIN_SWDIO PROBE_PIN_OFFSET + 1
​
// Target reset config
#define PROBE_PIN_RESET 6
​

	PICO		PICOW

STM32F769IDiscovery

This discovery board utilizes the STM32F769NIH6 Arm® Cortex®‑M7 core-based microcontroller with 2 MBytes of flash memory and 532 Kbytes of RAM.

• 4-inch 800 x 472‑pixel capacitive touch TFT color LCD with serial interface (on STM32F769I-DISCO only)

• Optional display accessories: HDMI and DSI adapters

• SAI audio codec

• Four digital ST MEMS microphones on DFSDM inputs

• 128‑Mbit SDRAM

• 512‑Mbit Quad-SPI flash memory

• Reset and user push-buttons

Pin Outs

CN9

PIN	GPIO_PORT	CONNECTOR PIN
1	PC0	A0
2	PH2	A1
3	PA0	A2
4	PA1	A3
5	PC2	A4
6	PC3	A5

CN8

PIN	GPIO_PORT	CONNECTOR
1	PB15	D0
2	PB14	D1
3	PG3	D2
4	PA0	D3
5	PG4	D4
6	PE14	D5
7	PD15	D6
8	PG5	D7

CN5

PIN	CONNECTOR NAME
1	E5V
2	IOREF
3	NRST
4	3V3
5	5V
6	GND
7	GND
8	VIN

CN4

PIN	GPIO_PORT	CONNECTOR NAME
1	PE3	D8
2	PB7	D9
3	PF6	D10
4	PF9	D11
5	PF8	D12
6	PF7	D13
7	GND
8	AVDD
9	I2C_SDA
10	I2C_SCL

CN11(Mikrobus)

PIN	CONNECTOR NAME	PIN	CONNECTOR NAME
1	AN	1	PWM
2	RST	2	INT
3	CS	3	RX
4	SCK	4	TX
5	MISO	5	SCL
6	MOSI	6	SDA
7	3V3	7	5V
8	GND	8	GND

CN3(Grove)

PIN	GPIO_PORT	SIGNAL
1	PF14	I2C_SCL
2	PF15	I2C_SDA
3		Vcc
4		GND

CN4

PIN	GPIO_PORT		SIGNAL
1	PF7		RX
2	PF9		TX
3		Vcc
4		GND

Arduino

	GPIO_PORT			SIGNAL
	PF14 - I2C4_SCL		D15	SCL
	PF15 - I2C4_SDA		D14	SDA
			AVDD	AVDD
			GND	GND
5 Volts, 800ma	PF7 - SPI5_SCK	E5V	D13	SCK
connected to 3.3V		D12	MISO	PF8 - SPI5_MISO
MCU Reset	PF9 - TIM32_CH4,SPI5_MOSI	NRST	D11	PWM/MOSI
3.3 Volts, 1.3 Amps	PF6 - TIM32_CH1,SPI5_NSS	3V3	D10	PWM/CS
5 Volt source from one of (E5V,USB,POE)	PB7 - TIM4_CH2	5V	D9	PWM
Ground	PE3	GND	D8
Ground		GND
External Supply must be < 11.5 Volts	PG5	VIN	D7
	PD15 - TIM4_CH4		D6	PWM
PC0 - ADC123_INP10	PE14 - TIM1_CH4	A0	D5	PWM
PH2 - ADC3_INP13	PG4	A1	D4
PA0_C ADC12_INP0	PA0 - TIM5_CH4	A2	D3	PWM
PA1_C ADC12_INP1	PG3	A3	D2
PC2_C ADC3_INP0	PB14 - USART1_TX	A4	D1	TX
PC3_C	PB15 - USART1_RX	A5	D0	RX

Azure-RTOS and startup

When the Azure-RTOS kernel is started, the first call is tx_initialize_low_level.s. The code does not have any specific STM32H7 code and appears to be CORTEX-M common ( to followup). This is where the SysTick frequency is setup as the base timer for the RTOS. There are two variables that define the frequency. SYSTEM_CLOCK = 520000000 <-- This value should be changed to match your CPU clock configuration SYSTICK_CYCLES = ((SYSTEM_CLOCK / 100) -1) The value is setup, see Figure 2