Miniscope

Preamble

Following on from Pocket ‘scope, the section on the Miniscope became too large and so was moved to here.

See also

What is it?

The Miniscope is an STM based PC/USB oscilloscope that can be built for less than $10.

From this post#7 on Low-Cost-Digital-Oscilloscope, using an STM32F303CBT6:

And if you truly want to DIY, there’s also this $10 O-Scope revisited. Same idea (using the fast A/D from an STM103 or a even faster STMF303, Miniscope v2d)

More here Hackaday Prize Entry: Oscilloscope for the Masses ???

Using an STMF303xD with 4 interleaved A/D, a maximum of 20 MSPS at 12 bits are possible, 20 times better sampling rate than the DSO138, and 12 bits instead of 8 (16 times better resolution). STMF303xD boards are pretty cheap, if you don’t mind real DIY

This is a PC/USB Scope, from tomeko.net:

This STM32F303CBT6 is what you want ((1PCS) STM32F303CBT6 IC MCU ARM 128K FLASH 48LQFP 32F303 STM32F303 new, $4.69):

STM32F303CBT6
STM32F303CBT6

which is an upgrade on the STM32F103C8T6

STM32F103C8T6
STM32F103C8T6

Note that there is a STM32F303C8T6 as well as STM32F303CBT6 – confusing 8 vs B. Not sure what the difference is yet – 8 bit)

This is cheap, STM32F103C8T6 Minimum System Developmen Board Module Core Learning For Arduino, $1.88 or STM32 Minimum System Development Board ARM STM32F103C8T6 Micro USB, $2

STM32F103C8T6 board
STM32F103C8T6 board

A programmer, ST-Link V2 Programming Unit mini STC8 STC32 Emulator Downloader T Jz, $1.93 or ST-Link V2 Programming Unit mini STM8 STM32 Emulator Downloader M89 mtauEB3C, $1.76 is required,

ST-Link v2
ST-Link v2

Unfortunately there are no STM32F303CBT6 boards, so you need to get a STM32F103C8T6 board and remove the STM32F103C8T6 and replace with a STM32F303CBT6, which is a bit of a pain:

This board is certainly not a STM32F103C8T6 board, Development Minimum System Module STM32 Board STM32F103C8T6 72MHz Gift Durable, £1.56 (the IC looks more like a STM32F030F4P6, see this board, STM32F030F4P6 CORTEX-M0 ARM 32 Bit 48 MHz Core Mini System Development Board USB):

s-l1600-36

How to use the “Blue Pill”

From Miniscope v2c on $3 STM32F103 board

For miniscope v2c:

  • leave PB2 in “0” position
  • for programming: set BOOT0 to “1” position, connect UART to PA9 and PA10 and reset board (TX to RX and vice versa) and run “Flash Loader Demonstrator” from STM or other loader of your choice
  • load stm32scope.bin from firmware archive
  • for normal operation: set BOOT0 to “0” position, disconnect and reconnect USB after programming
  • use A0 and A1 as analog inputs (adding protection similar to used by miniscope would be recommended, leaving ADC inputs floating generates also noise and also default version of device DLL is “calibrated” for 0…6.6V range)
  • as usual: connect to PC, install included driver (libusb), launch miniscope v4 with appropriate library (device interface)

stm32f103_board3

Front End

All that need to be added to the Blue Pill/Maple Mini boards is a front end for the probe:

Note that the v2d has upgrade the input divider to 27 kΩ + 22 kΩ

No values are given for the capacitors

These are SMD devices. For thru’hole components see gitlab:gr33nonline

Schematics:

Stripboard layout:

Miniscope v2d front stage board layout
Miniscope v2d front stage board layout

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