Comparison of processors:
Clock Flash RAM UART I2C SPI Timer GPIO ADC
MSP430G2553 16 16k 512 1 1 2 3 16 10b
ATmega-328 16 32k 2k 1 1 1 3 20 10b
LPC1114 50 32k 4k 1 1 1 4 21 10b
Stellaris 80 256k 32k 8 4 4 12 43 2x12b
STM32F030F4P6 48 16k 4k 1 1 1 5 15 12b
STM32F051R8T6 48 64k 8k 2 2 1 8 55 12b
STM32F4 168 1M 192k 6 3 3 12 82 3x12b
STM32F103C8T6 72 64k 20k 3 2 2 4 37 2x12b
CPU supply voltage is 3.6V. Input/output lines of the CPU do not tolerate higher voltages (such voltage can destroy the processor). Manufacturer recommends to limit current from/to any single line to 6 mA and total current to 48 mA. It should be possible to use current up to 20 mA without harm to the processor, however processor may work incorrectly in such case. There are two pushbuttons on the board, Reset and a user button. There are also two user LED-s (red and green). The LED-s may by disconnected to free processor lines for other use. There is debugging interface. The board provides serial port, however it does not work very well. In particular serial port will hang if chip start transmitting before the other end is listening. The board has two parts, one with debugging interface, the other with the CPU. The CPU part can be almost completely disconnected from debugging interface (only ground remain connected). In such case it is possible to supply CPU with lower voltage (down to 1.8V). The CPU is in a socket. After programming one can pull out the CPU and put in another circuit.
Documentation of the board, documentation of the processor
CPU supply voltage is 5V. Input/output lines of the CPU do not tolerate higher voltages (such voltage can destroy the processor). Maximal current from/to a single input/output line is 40 mA. Additionally total current should be at most 200mA. Exceeding those values can destroy the processor. For proper work it is recommended to keep current below 20 mA on each line. Arduino Uno board contains Reset button. There is also a LED available to user. Development support is limited to bootloader burnt into the CPU, which can write user program to flash memory. There is serial interface which can help in debugging. On original Uno board processor is in a socket, so that the board can be used as a programmer. Programmed processor can be pulled out from the board and put into another circuit. Our board are clones, most have processor soldered to the board. There are a lot of additional modules which can be connected to Arduino. Also, there is plenty additional instructions available on the net.
Documentation of Arduino, documentation of the processor.
We also have one Uno-compatible board that is switchable between 5V and 3.3V.
Arduiono Pro Mini is a smaller board, which contains only processor with few supporting elements, but do not contain serial interface and has simplified power supply. CPU is soldered to the board. This board is quite cheap. For programming one needs separate serial interface. There are also versions of Pro Mini designed to work using 3.3V. More precisely, the voltage stabilizer on board provides 3.3V and the board has 8MHz cristal oscilator, so that it will reliably work from 3.3V (ATmega processors with 16MHz cristal usualy work from 3.3V, but this is beyond specifcation and may sometimes fail).
Arduino Nano is similar, but slightly bigger than Arduiono Pro Mini. Unlike Pro Mini and like Uno it contains USB to serial convertor for programming and debugging.
CPU supply voltage is 3.3V. The CPU is one of many CPU-s using ARM architecture (more precisely Cortex-M4F). The CPU has single precision hardware floating point operations. Almost all CPU input lines tolerate 5V. Manufacturer recommends to limit current from/to any single line to 8 mA. It should be possible to use current up to 25 mA without harm to the processor, however processor may work incorrectly in such case. The board contains Reset button and two user buttons. There are three user LED-s. There is also micro-USB socket connected to the CPU. This allows programming the CPU to act as standard speed USB device. There is debugging interface. The board provides serial port which works well. Let us note that debugging interface uses exactly the same CPU as user CPU -- simply processor in debugging interface is running appropriate program.
After initial release of the processor manufacturer (TI) decided to change name from Stellaris to Tiva. Currently one has to use Tiva as name to find information on TI pages. We have old version of the board -- newer one (using Tiva name) removed some errors.
Documentation: TI page for Tiva Launchpad.
This board just contains the STM32F103C8T6 CPU and a few supporting elements. The CPU supply voltage is 3.3V. The CPU is one of many CPU-s using ARM architecture (more precisely Cortex-M3). For debugging one can connect external debugging interface. There is mini-USB socket connected to the CPU. One can program CPU to act as a standard speed USB device. There is a LED on board connected to line PC_13.
Documentation:
This board just contains the STM32F030F4P6 CPU and a few supporting elements. The CPU supply voltage is 3.3V. The CPU is one of many CPU-s using ARM architecture (more precisely Cortex-M0). For debugging one can connect external debugging interface. There is mini-USB socket on board, but it can only be used to supply power. There is a LED on board connected to line PA_4. If the PA_4 line is needed for different purpose the LED can be disconnected removing jumper marked "LED". The PA_13 and PA_14 are normally used by debugging interface and can not be used for other purpose. The PA_0 up to PA_7 and PB_1 lines are analog capable but can maximally tolerate 3.3V. The PA_9, PA_10, PA_13, PA_15, PF_0 and PF_1 lines are 5V tolerant.
This processor is interesting, because it is one of the cheapest 32-bit processors and is likely to become quite popular.
Documentation
This board contains STM32F051R8T6 CPU. Like in all Discovery boards CPU supply voltage is 3V. The CPU is one of many CPU-s using ARM architecture (more precisely Cortex-M0). Most of CPU input lines tolerate 5V. The board contain Reset button and a user button connected to PA_0. There are two user LED-s: blue connected to PC_8 and green connected to PC_9. Board contains debugging interface (using STM32F103C8T6). Documentation:
Like in all Discovery board CPU supply voltage is 3V. The CPU is one of many CPU-s using ARM architecture (more precisely Cortex-M4F). The CPU has single precision hardware floating point operations. Most of CPU input lines tolerate 5V. Manufacturer recommends to limit current from/to any single line to 8 mA. It should be possible to use current up to 25 mA without harm to the processor, however processor may work incorrectly in such case. The board contain Reset button and an user button. There are four user LED-s. Board contains accelerometer, microphone and audio DAC with amplifier. There is also micro-USB socket connected to the CPU. One can program CPU to act as a (high speed) device or as a USB host (USB OTG). Board contains debugging interface (using STM32F103C8T6) connected to mini-USB socket.
Documentation: