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What co-processor would you like with your prop? — Parallax Forums

What co-processor would you like with your prop?

Cluso99Cluso99 Posts: 18,069
edited 2010-12-24 10:48 in Propeller 1
My modular Blade pcbs are nearing completion. They are 1.75"x1.75" square pcbs that fit into Hammond boxes.

As a final step, I a proposing to add a high powered co-processor pcb. I am looking for a small footprint PQFP package up to 64pins if possible. It would be nice to have USB OTG support and at least 8x10b ADC. Comms to the prop will be via 2 pins - either I2C(TWI) or Serial. All I/Os will not be brought out! I would like >64KB internal SRAM.

Currently, the best candidates seem to be the Atmel AT32UC3B0256-A2UT & AT32UC3B064-A2UT but do not satisfy all my requirements.

Does anyone have a better suggestion?

Comments

  • jazzedjazzed Posts: 11,803
    edited 2010-12-23 16:10
    I have an AVR32 development kit. I've never opened it. The problem is I don't want to pay $300 for the programmer.

    I recently bought a PIC32 USB eval board for $50 mainly because of my background with MIPS architecture. I was able to program it with no other tools required within a half hour of opening the package. But I haven't had much time with that since I'm busy with other Propeller related stuff (The TinyTwoWire boards should be order-able early next week for example). The chip without hardware trace pins is available as TQFP64 (.5mm pitch).

    MIPS32 is a standard RISC architecture machine the PIC32 runs at 80MHz at 1MIPS/MHz. It has 128K RAM and 512KB flash on board the chip with USB2.0 OTG and 16 10 bit ADCs. Here's a good PIC32 summary page.

    I'm sure ARM will also get lots of suggestions.
  • Cluso99Cluso99 Posts: 18,069
    edited 2010-12-23 20:19
    Steve: Like you, these days I dislike all the different programmer requirements. This is one reason why I chose that Atmel part. The code is auto-booted by USB so only a PC and a USB cable (camera/phone) is required. Another reason is because I am using the ATtiny too, so the same basic instruction set makes sense.

    Of course, as soon as the PropII is available, a pcb like this will be done - just cannot wait any longer :(

    I am using the Changed ATtiny84-20SSU (SOIC14 0.15" with 1.27mm pitch) ---> ATtiny88-AU (TQFP32 [EMAIL="9x9@0.8mm"]9x9@0.8mm[/EMAIL]) so it is easy to hand solder, even for those who haven't soldered smt before. Are you (and anyone else) using this part? Perhaps we could combine an order to get the price breaks? Programming is easy (SPI) - only 4 prop pins required so I have a special header for this which will plug into any of the prop expansion ports Bill, you and I & others are using.

    I looked at the PIC32MX795 ($7.95 at Sparkfun). Nice chip but not so sure about the programming of it - certainly not as simple as Atmel.
  • BatangBatang Posts: 234
    edited 2010-12-23 20:25
    Arm Cortex 3 such as the LPC175x.

    Cheers
  • jazzedjazzed Posts: 11,803
    edited 2010-12-23 21:36
    Cluso99 wrote: »
    The code is auto-booted by USB so only a PC and a USB cable (camera/phone) is required.
    Please provide a reference link so I can read and understand what you mean.

    I like AVR too, but I'm not paying $300+ for a programming tool to use the AVR32 line.

    The TinyTwoWire board uses a DIP atTiny84, but can be programmed in circuit with the $50 ATDRAGON. I was able to rescue all my atTiny85 parts with the ATDRAGON :)
  • Cluso99Cluso99 Posts: 18,069
    edited 2010-12-23 22:30
    The AT32UC3xxx come preprogrammed with an internal bootloader in a protected section of Flash which permits downloading from the PC over it's USB bus. http://www.atmel.com/dyn/resources/prod_documents/doc7745.pdf
  • jazzedjazzed Posts: 11,803
    edited 2010-12-23 22:47
    Cluso99 wrote: »
    The AT32UC3xxx come preprogrammed with an internal bootloader in a protected section of Flash which permits downloading from the PC over it's USB bus. http://www.atmel.com/dyn/resources/prod_documents/doc7745.pdf
    Great! Don't know how I missed that. Guess I'll be spending time with my EVK1105 now (well later really) :)
  • Cluso99Cluso99 Posts: 18,069
    edited 2010-12-23 23:24
    Yes, the EVK1104 & EVK1105 look like excellent pcbs :)
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2010-12-23 23:36
    The great divide is between PICs and AVRs, but then it begins to get seriously complicated by a vast array of individual chips. You've chosen a rather ambious co-processor when I suspect that most want something they are already familiar with.

    The PIC 16F57 and 16F87 are nearly pin compatible with the retired SX28 and SX18 Dips. If people really want DIP packages, that might be one way to go. But I suspect the AVR/Arduino crowd will chime in with complaints of being ignored.

    In sum, you are going to have to ignore somebody just to get started, maybe ride the AVR/Arduino wave for this one.
  • BatangBatang Posts: 234
    edited 2010-12-24 01:03
    Also the Arm 7 LPC213x as lower tier device.

    Both the above ARM chip and the Coretx I mentioned earlier can load the flash with the built in boot loader via a serial port.

    Free tools and flash loaders are available.

    Cheers
  • Cluso99Cluso99 Posts: 18,069
    edited 2010-12-24 01:14
    As I said, I want a powerful chip, SRAM wise, with USB & ADC. Since I am using an ATtiny88 (was going to use an ATtiny84) elsewhere in this project, an AVR makes the most sense to me. I don't know either the PIC or the AVR. I am not looking for an SX18 or SX28 replacement, as obviously I don't know anything about them.

    Chip cost is not a concern for what I can get, and cheaper less powerful compatible versions are more readily available. Maybe I am wrong, but I don't see a lot of people wanting these pcbs. This is just 1 of 8 modules coming.

    I guess I am asking in case I missed something extraordinary (like the Prop II).
  • BatangBatang Posts: 234
    edited 2010-12-24 03:34
    What about a LPC2388.

    It has the memory, more peripherals than you can throw a stick at including a SD card interface.

    http://www.nxp.com/#/pip/pip=[pip=LPC2388]|pp=[t=pip,i=LPC2388]

    http://www.gnuarm.com/
    http://www.codesourcery.com/sgpp/lite/arm/

    Cheers
    LCP2388.gif
    559 x 665 - 38K
  • Cluso99Cluso99 Posts: 18,069
    edited 2010-12-24 04:51
    LPC2988 - nice ARM7 chip $15ea. Certainly lots of peripherals USB, Ethernet, CAN, etc etc. LQFP144 @0.5mm pitch. Trying to stick with less pins to hand solder??
  • LeonLeon Posts: 7,620
    edited 2010-12-24 05:29
    The MIPS core in the PIC32 has a big advantage over the ARM core in that outputs can be toggled at the processor clock speed. ARM chips use the AHB peripheral bus which is rather slow.

    All ARM chips with USB can have a USB boot-loader, but it might have to be developed and has to be programmed into the chip.

    Another option if anyone wants an ARM co-processor for the Propeller is to use an LPCXpresso or mbed board:

    http://ics.nxp.com/lpcxpresso/

    http://mbed.org/

    The latter uses similar software to the Arduino, except that it's web-based.

    There is also the similar ST32 Discovery board, which costs $10!

    They could easily be mounted on a Propeller Proto board.

    Microchip has a similar little board which comes with a PIC24 and a dsPIC. They run at 40 MIPS; the latter would be ideal for adding DSP to the Propeller.

    All those boards have the advantage that building a Propeller board for them is much easier than developing an ARM board and are what I'd use, but I'm lazy. That's what I did with my XMOS co-processor, I was able to make the PCB at home. I've got all those boards, if anyone needs any more information.
  • HumanoidoHumanoido Posts: 5,770
    edited 2010-12-24 10:48
    A Propeller II.
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