Once more into the breach
For a few weeks now I've been designing a board that (hopefully) will be compatible with the new Due (at the tool chain level at least). I say "hopefully" because despite saying that the Due would sport the SAM3U4E Arduino now say it could be another processor.
No matter, I won't finish the design until we know, it probably won't affect much.
This will not be a competitor to the Due unless Arduino depart from their current MO of creating simple boards which I doubt, I see it more as a big brother.
So meanwhile I have a 98% finished schematic, PCB component layout and design document and I'm wondering if anyone is interested. So far there hasn't been much interest in the real Due so I don't hold out much hope for a "similar" but you never know.
Here is a list of the specs as the design currently stands.
• SAM3U4E 96MHz ARM Cortex-M3 processor.
• An 80-pin backplane with 5 addressable daughter boards and provision for memory expansion and/or fast IO.
• Sub addresses for each daughter board allowing up to eight devices per board to be addressed.
• Debugging support with JTAG, memory-mapped strobe output and two hardware-controlled pulse outputs available on a debugging header.
• Software control of power to the entire system.
• Software control of power to seven sub systems on the core board and one external system.
• Provision for plug-in power supply modules that replace on-board regulators, can be used for high-current or energy-harvesting PSU etc.
• 512k bytes of external SRAM, expandable to 22.5Mb (directly addressable) and 880Mb (using bank switching).
• Separate very accurate RTC with temperature-controlled oscillator.
• Battery backup for SRAM, RTC and the SAM3U’s internal RTC/RTT.
• LiPo battery charging from USB or VIN inputs.
• Onboard temperature sensing.
• Serial EEPROM for non-volatile system parameters.
• High-speed 4-bit microSD interface.
• I2S interface for CODECs, DACs etc.
• Eight 6v-tolerant analogue inputs.
• A total of seven serial ports, five internal and two on an external UART.
• 32 digital IO with 5v or 3.3v support in both directions.
• 16 high-current digital IO with 5v or 3.3v support in both directions.
• 3.3v and 5v IO selectable in groups, 16 of the digital IO lines have a third option of external power (for high-current IO such as servos).
• All IO brought to popular GVS (Ground-Volts-Signal) format headers to make direct connection of sensors and servos easy.
• Built-in 2x8 LCD, expandable for standard character LCD types.
• Built-in interface to 4D Systems graphics LCD with touch panel.
• Four user pushbuttons and LEDs.
• Built in buffered RS-485, RS-232, SPI, TTL, I2C/SMBus, 1-Wire and S2N (Simple Serial Network) interfaces.
• Backplane for four on-board S2N IO modules.
• Network support for XBEE, Wi-Fi, Bluetooth, Ethernet etc with plug-in XBEE-footprint modules.
And a proposed PCB layout.
I have to say it's beginning to look like too large a project for one person to prototype, debug and write all the drivers for in a reasonable time frame and with new boards like the RPi out I'm wondering about my sanity in proceeding. To be fair though this is a vastly different beast to the Pi and other offerings so maybe.
The schematics and design overview document are available to anybody that is interested, email me for a copy.
I do have the interest of a well-known company to manufacture should it get to that point but if there is little interest it won't so don't sit on the sidelines to see what happens because without help nothing will
That's all for now, any questions gladly received.