Which arm microcontroller to choose?

There are a lot of good answers; and I agree with all of them.

If I had to choose between boards, and I could only buy one board, I would go for the STM32F429 board or the STM32F776 board.

This is mainly because those boards cover a very large variety of interfaces and peripherals, while also running at very high speeds. The mentioned Discovery boards are arduino-compatible (there are shield-connectors on the bottom side).

Thus you can easily use it as a 'development workbench' to prototype a project or product, and when you have something working, you can determine the minimum requirements and purchase a smaller chip/board that will be able to handle the job.

-That's one way of doing it.

But as for myself, I tend to purchase a bunch of low-cost STM32F103 boads.

I've become a top-notch-o'holic, however, even though the Cortex-M3 based STM32F103 boards only runs at 72 MHz, they offer a very, very good value for the price.

The board is an arduino-compatible board; it gives you 16+15 GPIO pins (one full 16-pin port and one port with 15 pins available).

This board can be hacked if you wish, so you can have two full 16-pin ports (I did that once; you'd need to unsolder one of the SMD resistors and replace it with a 0-Ohm resistor).

GPIO pin speeds are up to 36 MHz on all pins. The Timers can be connected to an advanced DMA; it allows you to make the timers automatically update their registers (reconfigure-on-the-fly) in addition to controlling a second DMA. The timers can also be cascaded, so that one timer can trigger one or more timers, which can again trigger more timers, and so on. (The STM32F4 and STM32F7 can of course do this as well).

Links:

• The STM32F103 Board ($2.6)
• The ST-Link v2 programming dongle ($2.7)

There are a lot of good answers; and I agree with all of them.

If I had to choose between boards, and I could only buy one board, I would go for the STM32F429 board or the STM32F776 board.

This is mainly because those boards cover a very large variety of interfaces and peripherals, while also running at very high speeds. The mentioned Discovery boards are arduino-compatible (there are shield-connectors on the bottom side).

Thus you can easily use it as a 'development workbench' to prototype a project or product, and when you have something working, you can determine the minimum requirements and purchase a smaller chip/board that will be able to handle the job.

-That's one way of doing it.

But as for myself, I tend to purchase a bunch of low-cost STM32F103 boads.

I've become a top-notch-o'holic, however, even though the Cortex-M3 based STM32F103 boards only runs at 72 MHz, they offer a very, very good value for the price.

The board is an arduino-compatible board; it gives you 16+15 GPIO pins (one full 16-pin port and one port with 15 pins available).

This board can be hacked if you wish, so you can have two full 16-pin ports (I did that once; you'd need to unsolder one of the SMD resistors and replace it with a 0-Ohm resistor).

GPIO pin speeds are up to 36 MHz on all pins. The Timers can be connected to an advanced DMA; it allows you to make the timers automatically update their registers (reconfigure-on-the-fly) in addition to controlling a second DMA. The timers can also be cascaded, so that one timer can trigger one or more timers, which can again trigger more timers, and so on. (The STM32F4 and STM32F7 can of course do this as well).

Links:

• The STM32F103 Board ($2.6)
• The ST-Link v2 programming dongle ($2.7)