Switching to ARM MCU from STMicroelectronics

After testing and using several microcontrollers, mainly Atmel type, I wanted to switch to a more professional microcontroller. First of all, all main microcontroller suppliers (ST, TI, NXP) are making ARM based controllers. So, to be ready for the future, ARM it wil be.

The second choice is about the supplier. In the professional field I met some people who used the STM32 chips and were very satisfied about the possibilities and development tools.

So I started my first test with the STM32F103C8T6 development board, so-called Bluepill. Very cheap, a few EUR. This one worked good en was easy to program with a ST-LINK V2 USB programmer (about 7 EUR). I used Platform IO to program this controller.

To make my own project, I have to be able to make my own PCB and using an ARM controller. I found 1 ARM controller with DIP casing, the rest were SMD. The next step was to learn SMD soldering. That took a little while, but after looking a some Youtube video’s I managed to solder the first breakout board.

The test with this board worked fine, so I made my own development board (PCB).

The schematic is here:

After that I wanted to use a Low Power version of this controller. I was really happy to see that with STMicroelectronics you can really easy switch to other controllers without changing you PCB design. All pins are on the same spot! I used the STM32L151C8T6 (LQFP-48 housing 7×7 mm, 9.85 footprint).

It was very hard to get this one connected to the programmer and software. It took a while before I found that the Clock crystals were not fitted for this controller. So at last I removed all crystals and then I could program the controller. There was also an advantage of that: It used less surface on the PCB and is lower in cost. This processor is still running on 2 MHz internal clock.

One capacitor (that can be replaces by SMD version) two resistors and one controller.

Now I gone test the programming capabilities of this Low Power controller. My goal is to replace the ATtiny84 with this one and make a smaller PCB with less power consumption.

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