Fighting with computers

Computers are not always friendly.

Saturday, February 07, 2015

Maple Mini looking good

This week I received a real bargain I wanted to test as a better candidate to be able to control several DC motors in closed loop.

I have already tested the STM Nucleo 401 board and I get one 32 bit, signed, hardware encoder input on timer 2 and three more unsigned, 16-bit hardware encoder inputs on other timers. Unfortunately timer 5 was taken by the mbed library I was using. Nucleo is a solid platform and using the cloud IDE actually is not big deal for me.

But now I have got a Maple Mini for $4 and I have to tell you I am totally sold. It is so much faster compared to an ATMega Arduino that I am positive it can do the work for controlling two DC motors closed-loop and most likely it can do four or more.

The board can handle up to 16 external interrupts, enough for 8 encoders, and it can produce 12 PWM 16-bit resolution outputs (a far cry from 8 bit PWM from Arduino, though I am not sure that will have any impact on the system performance) plus plenty of memory (128K flash, 20K RAM), serial ports and other nice touches.

Like any other Cortex-3 it runs off 3.3V power, which I thought it will be a pain as encoder circuit is rated at 5V, but a quick test revealed encoder seems to be working happily when powered at 3.3V too. That saves me some trouble with interface and gives me more freedom as not all the input pins are 5V tolerant.

Though the Maple family has been around for quite a while (2009) I have never used it before. And my first experience has been a blast too, because the Arduino IDE clone is what they use, so it all seems pretty familiar for long-time Arduino users.

I guess that sooner or later I will need to venture in some of these detailed user manuals for setting some feature on, but for the moment the sample programs and online help are being good enough.


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