Computing stuff tied to the physical world

The HY-Tiny can also act as BMP

As last example in this “let’s make an ARM programmer” series, the HY-TinySTM103T:

Screen Shot 2015 11 18 at 12 29 24

It’s a great little STM32 board with a nice set of features: 128 KB flash, 20 KB RAM, the usual mix of peripheral interfaces, and a little programming + debugging header at the bottom. We’re going to turn the one below (on the right) into a Black Magic Probe:

DSC 5262

… which can then be used to program and develop code on the one on the left!

Here is a little breakout PCB, this one goes on the bottom of the HY-Tiny:

Screen Shot 2015 11 18 at 13 46 15

There’s the same header on the left side as in the previous articles, i.e.:

  1. 5V (power feed)
  2. GND
  3. SWCLK
  4. SWDIO
  5. TX (to be connected to the target’s RX)
  6. RX (to be connected to the target’s TX)
  7. 3.3V (power feed, 100..200 mA max)
  8. NRST

(this is top-to-bottom, but seen from below, since the board sits underneath the HY-Tiny!)

The solder jumpers are there to allow changing the pinout: cut them and re-wire as needed. Note that only pins 2..7 are used when programming a second HY-Tiny as show above.

There’s room to add a 1..10 kΩ resistor on this board, as pull-down for the A0 pin. This is necessary if you use this BMP build by Rick Kimball (, because it expects a different pin to control the USB disconnect function.

An advantage of using the HY-Tiny over the STM32F103C8T6 board from the previous article, is the compact size and that it has 2x as much flash memory, for future expansion.

But as with that board, you will need to figure out a way to get the BMP software onto the HY-Tiny. One option is serial boot mode, which is easy to activate: keep the ISP button (left) pressed, while briefly pressing the RST button (right). After connecting up at least the A9, A10, and GND pins to your serial interface board, activate the serial boot mode and use either the stm32flash or the utility to upload the BMP firmware.

That’s it. You now have three ways to start developing software for STM32-type µC’s!