pslab-mini-hardware

This repository contains the PSLab-Mini hardware design files. PSLab-Mini is a scaled-down version of the PSLab board, aiming to provide instruments for doing signal measurements. It consists of an Oscilloscope, a Logic analyzer, and a Multimeter.

It also integrates an ESP chip in conjunction with the main MCU(STM32), for enabling wireless connectivity via the board.

• Firmware: https://github.com/fossasia/pslab-mini-firmware

PCB Layout

Front Side	Back Side

Prototype Pictures

Prototype Case

The PSLab Mini is designed to use Raspberry Pi 3/4 Cases, which are already widely available, without any modification.

All the ports remain accessible in the casing (USB, BNC Connectors, and battery connector).

Communication

• Our chat channel is on Gitter here at PSLab channel
• Our Website PSLab Website

Platform

• Main Microcontroller : STM32H563RIT6
• Secondary Microcontroller : ESP32C3
• Compiler: gcc-arm-none-eabi
• Programming Tool:
  • For uploading the bootloader onto the board: STLink/Any other ARM programmer
  • For uploading the firmware onto the board: Directly using USB (OpenBLT bootloader is already present on the board)

Parts list

• STM32H563RIT6 - Main Microcontroller
• ESP32C3 - Secondary Microcontroller(for internet connectivity)
• W25Q32JV - 32 Mega bit(4 Mega Byte) flash for ESP32
• OPA356AIDBVR - 1 channel High-Speed CMOS Op-Amp
• TLV9001IDCK - 1 channel Low-Speed CMOS Op-Amp
• IP5189T - Battery management chip
• AMS1117-3.3 - 5 V to 3.3 V buck converter
• MT2496 - 5 V to -2 V, inverting buck converter
• SP0503BAHT - ESD Protector
• Assorted resistors & capacitors

Details of the project

Design Goals

• Compact and manufacturable: All components placed on one PCB side

Core functionalities

• Oscilloscope

  • 2 channels, 12-bit ADC (at 5MSPS)
  • Uses BNC connectors to connect probes to the board
  • Higher sampling rate than the current PSLab Board

• Logic Analyser

  • 2 Channels

• Multimeter

  • AC/DC voltage, resistance, capacitance, frequency

Technical Requirements

• Interfaces
  • Open Toolchain : compiles with gcc(gcc-arm-none-eabi)
  • ADC : ≥ 2 channels, 12-bit
  • 2 x UART, 2 x SPI, 1 x I2C exposed from the chip pinout(STM32) Out of which, it has the following segregation:
    • 1 x UART, 1 x SPI - Used to interface between the ESP32 and STM32
    • 1 x UART, 1 x SPI, 1 x I2C - exposed to external headers to connect various peripherals to the board.

Pinout Used on the board.

STM32

GPIO

Pin Name	Pin (on Microcontroller)	Type
GPIO 0	PA5	Analog Pin
GPIO 1	PA6	Analog Pin
GPIO 2	PA7	Analog Pin
GPIO 3	PC4	Analog Pin
GPIO 4	PC5	Analog Pin
GPIO 5	PB0	Analog Pin
GPIO 6	PC8	Digital Pin
GPIO 7	PC9	Digital Pin
GPIO 8	PA8	Digital Pin

Instruments

Pin Name	Pin (on Microcontroller)	Type
LA1	PA3	Logic Analyser Channel-1
LA2	PA2	Logic Analyser Channel-2
FQY	PA4	Frequency Measurement
VOL	PC0	Voltage Measurement
RES	PC1	Resistance Measurement
CAP	PC3	Capacitance Measurement

BNC Connectors

Connector Number	Pin (on Microcontroller)	Type
CH1	PA0	Oscilloscope Channel-1
CH2	PA1	Oscilloscope Channel-2

Buses

UART_1	Connected to ESP32
SPI_2	Connected to ESP32
UART_6	Connected to External header pins
SPI_3	Connected to External header pins
I2C_1	Connected to External header pins

ESP32

Buses

SPI_1	Connected to External NOR flash
UART_1	Connected to STM32
SPI_2	Connected to STM32

Reset functionality of the board

The reset button on the board resets both the STM32 and the ESP32 simultaneously.

In addition, the STM32 can reset ESP32 through an output pin:

PB5 (STM32) → CHIP_EN (ESP32)

Documentation related to the microcontroller

STM32

• Datasheet
• Reference manual
• HAL and LL documentation

ESP

• Datasheet
• Reference manual