Fresh look at microcontrollers

    This short post may slightly remind you of some market research on the theoretical note " Are microcontrollers out of date? "

    One of the small crafts that I am currently working on has prompted the study of microcontrollers and finished boards. In particular, you need a fairly compact controller with 20 inputs / outputs, and allowing you to act as a slave USB device. The first glance fell on Teensy , quite compact, on the Atmega32U4 chip. Confused only the price, $ 24 for a device with soldered legs, plus shipping. Just a little less than half the price that I ordered in April and arrived just today, the Raspberry model B (hooray!).
    Prices for Arduino, Propeller are also unpleasantly surprised.
    Actually, I visited the idea of ​​just putting the chip itself on a printed circuit board and not bother with a separate controller, but Atmega32U is not cheap, about 4 euros apiece (32U2) 5.5 euros for 32U4, and their prices do not decrease, but, on the contrary, increase.

    With the USB series AVRs (90USB, 8U. 16U. 32U) it is also confusing that the trial firmware that I did as examples took about 18KB, mainly occupied by the USB code (LUFA / some kind of home-grown from Teensy ), and flash memory in half of these devices is already smaller. What is there with the consumption of RAM, generally speaking, it’s hard to say whether 1KB is enough? Without any experience in optimizing C code, I absolutely did not want to climb into this jungle.

    And then I suddenly stumbled upon the announcement of a new line of XMC4000 processors based on Infineon's ARM M4F with a stated price of $ 1.5 to $ 4, very impressive (relative to AVR) characteristics, like 120MHz, 1MB flash memory and 160KB RAM. MSP430 got a little nervous.
    And there, on the page advertising processors, there was such an amazing thingas a starter kit based on the older (XMC4500) of these processors, for only 10 euros, including many charms such as USB, SPI, 3 x I2C, 3 x I2S, 3 x UART, 2 x CAN, 17 x 12 ADC bit, 2 x DAC, 31 x PWM. Much more than I need. In addition, there are two chips on the board, one of which can be used for debugging via the second USB port, or it can literally be broken off from the board and used in some other way. There are, of course, less entrances and exits than Arduino Mega, and the price is 4 times lower than Arduino Due. For connoisseurs, there is an option with soldered Ethernet, a latch for SD cards and a flash memory of 4 MB, but already more expensive, for 30 euros.

    It turned out that the miracle device was not alone, and the Freescale Freedom Board was found nextwith a similar price of 10 euros, a processor based on the Cortex M0 +, and even pinout compatible with Arduino, with some incredible pribludy, such as an accelerometer.

    It is not worth paying attention to the STM32F0DISCOVERY (Cortex M0) and STM32F3DISCOVERY (Cortex M4) boards with prices of 8 and 12 euros, from STM .

    All the charms of the processors on the Cortex M0 / M4 can be attributed to the fact that they are made not only in cases that can not be manually soldered , even in the DIP8 case.

    Agree, it’s worth a lot to think about choosing a microcontroller in your next hand-assembled device.

    PS For my project, I took Teensy on ATMEGA32U4, for its compact size, and just in case, Olimex LPC-P1343 .

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