Many people have suggested upgrading from an 8-bit microcontroller to a 32-bit microcontroller, perhaps one that "can run Linux". Since all the RepRap firmware is written in C or C++, in theory it should be "easy to port"(*) to any microcontroller. Here are some of the suggestions so far:
R2C2 RepRap Electronics
A nice, compact board with pretty much exactly what we need and no extras that we don't. A good cost and pretty well powered board that should meet our needs well. Its also small and compact. It claims to be un-brickable and looks to be fairly rugged.
Price point: around $80/board at our quantities. Features
* Great documentation * 250MHz ARM9 CPU * 64 MB DDR-RAM * 4 MB NOR Flash * Customizable 5K LUT OpenCore FPGA * 1 micro SDHC Card slot * USB2 480Mbit/s Host(2) / Slave(1) * 1 10/100 Ethernet * 8 TTL UART * 33 DIO, SPI and I2C interfaces * Watchdog Timer * Optional BB-RTC, CAN bus, WiFi * Power-over-Ethernet Ready * Fanless Operation from -20°C to 70°C * Small size (67mm x 75mm) * Low power (400mA @ 5V) * Unbrickable, boots from SD or Flash * DevKit includes base-board+enclosure * Boots Linux 2.6 in less than 3 seconds
Good mix of low price and stripped-down feature set. On-board LCD and touchscreen support. Good relationship with Bunny is a plus. New boards don't have chumbilical connector populated; we could get this added for peanuts.
Price point: Fully assembled chumby one w/ all the toppings runs $119, so I'm guessing we can get the board at ~$50-$60. Features
* Open-source * 454 MHz ARM * 64 MB RAM * WiFi * boots off MicroSD * backlit 3.5" LCD, touchscreen * Breakout header: "Chumbilical" o +5V o 1 SPI interface o audio output o video output o 2 USB channels o 1 GPIO * Est. cost ~$50
Bug Labs bugbase
Tricked-out DeLorean of ARM modules. Nice feature set, way too pricey. May be worth talking to them to see if they're considering a stripped-down version, but a long shot.
Price point: Fully assembled retails at $450; probably could get a raw board for closer to $200 in quantity. Features
* Open source * 532Mhz ARM 11 microprocessor * 128 MB SDRAM * 32 MB on-board flash storage * MicroSD card interface (support up to 16GB) * Integrated 802.11b/g WLAN * Bluetooth 2.0 + EDR * USB 2.0 OTG High Speed host interface * Breakout: 4 BUGmodule interfaces o + Four UART serial links + 4-channel SPI interface + I2C (400 kbits) interface/4 channels + I2S interface/ 2 channels * 10/100 Ethernet MAC * JTAG/ICE support * Serial debug port * Smart power management support * Battery-backed real-time clock * Way too expensive: retails for ~$450, could probably negotiate a clean board wholesale down to $125
Leaf Labs Maple
Arduino clone. Not sufficient pinnage or muscle. Open-source; could potentially be modified to work for us. Features
* Open-source * STM32 ARM Cortex-M3 @ 72MHz * 20 KB SRAM * 128 KB Flash * Breakout header: arduino-compatible o Arduino pins * Retails ~$50, could probably wholesale down to ~$30
Xduino extends Arduino to run on ARM processors. Currently Xduino is known to work with the
- STM32 ARM Cortex-M3 at 72MHz
Coridium ARMmite PRO
Another underpowered arduino-like board, but the price point is nice— $30 retail. Features
* ARM7 CPU running at 60 Mhz * 32K Flash memory and 8K SRAM memory * 24 TTL compatible digital I/O * 7 10-bit A/D converters, 100 KHz sample rate * 8 Hardware PWM channels * internal supplies of 5V, 3.3V and 1.8V
2 x MCP3208 - 8 channel, 12 bit ADC, SPI, $2.64/chip 4 x MCP23S17 - 16 channel GPIO, SPI, $0.95/chip 1 x TLC5940 - 16 channel PWM, $1.30/chip
ADC: 16 GPIO: 64 PWM: 16 TOTAL: 92
Cost: 2.64*2+0.95*4+1.30*1+0.50*8 Operating System RTAI Realtime linux extension, pretty standard eCos
* Includes TCP/IP stack * Includes USB stack * Active dev community * Supports just about every embedded platform you can think of
* Pretty much the same as eCos, shares some of the same modules * Reputedly smaller than eCos * Two parallel projects: a GPL version and a licensed support version
Runs Linux, USB, Ethernet 10/100, etc.
An implementation of the 32 bit MIPS CPU.
32-bit ARM based microcontrollers
The problem with ARM based microcontrollers is that they are only available in SMD houses (not DIL).
The good thing about ARM are:
- good and mature architecture (since 1984!, originally designed for Archimedes computers to replace the 6502 and 6510)
- low power (high mips/watt)
- Good open source compiler (GCC) and IDEs support
- Available from many firms and suppliers (e.g. LPCXpresso Boards)
- Active development (10/27/2011, eetimes.com: ARM unveils 64-bit architecture Quote: "...ARM Holdings has announced that its next-gen ARMv8 architecture will include the firm’s first 64-bit instruction set, pushing ARM-based processors into new segments of the consumer and enterprise markets...This, he said, “would bring the advantages of energy-efficient 64-bit computing to new applications such as high-end servers and computing, as well as offering backwards compatibility and migration for existing software through a consistent architecture."...Indeed, the first processors based on ARMv8 will only be announced sometime in 2012, with actual server prototypes running on the new architecture expected in 2014...")
Please note that using ARM does not necessarily mean to abandon Atmel AVR. Atmel AVRs could be used as a dedicated xyz-extruder-control or other low level support.
yet another ARM controller from grael
(does this have a name yet?)
- Arm Cortex M3
- RepRap forums: "Build thread, 100 pin STM Arm Cortex board with driver chips."
No longer vaporware! See photos of it controlling a CNC at http://grael-minifactory.blogspot.com/