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LaunchCAN?


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Sorry I am pretty bad at coming up with catchy names. :lol:

 

Anyways, my proposal at the moment involves a "double" booster size of 100x50mm. Which will allow it to sit nicely in a 1455C case from Hammond as well. It will have properly broken out headers for LaunchPad Booster packs.

 

Anyways some of the initial specifications I want on the board:

 

  • [*:vili5prf]TI MSP430G2553 TSSOP-28 (or using headers to a LP) (might need something "bigger"?)
    [*:vili5prf]Microchip MCP2515 CAN Bus Controller aka "SPI<->CAN Bridge"
    [*:vili5prf]TI SN65HVD235 CAN Transceiver w/Auto-Baud Loop Back checking
    [*:vili5prf]Bluehash's OLED display
    [*:vili5prf]Anaren CC110L Module
    [*:vili5prf]TI TCA8418 I2C Keypad Controller attached to a 4x3 or 4x4 Button Keypad
    [*:vili5prf]TI TCA6408A I/O Expander attached to 8 Status LED's for CAN Bus and system information
    [*:vili5prf]National LM34910 Switching Regulator
    [*:vili5prf]CANOpen DE-9 Connector (NOT compatible with SPF's OBD-II cable)
    [*:vili5prf]Phoenix M12 CAN Connector

 

One thing you guys may be able to help me with, is how to use 2 power sources and have the system automatically switch from one to the other without user intervention. Never tried anything like that before. Currently in my head, the National LM34910 will provide approximately 3.3V at 500mA with a input range of 10 to 26V making it compatible with both 12V CAN Bus networks (automotive) and 24V CAN Bus networks (Industrial stuff), however a battery back up would provide for power using a TPS780 which will allow the MSP430 to power itself from 3.3V to 2.2V due to the selection pins when there is no power applied to the CAN Bus connectors.

 

I might need something bigger then a G2553, however, my CANBus code when I did it on a Arduino was only 4.5K, and nearly 1.5K is automatically taken up by the bootloader when you write your program onto the Arduino, so it might just fit on a mere 16kB, but I am not sure at the moment. Might need a bigger chip, and I feel I would not have the memory space required to implement a SD Card storage on the G2553 at all. Any suggestions are welcomed.

 

But there you have it a little do it all industrial interface board. I'll post schematics and pictures of the PCBs in due time. :D

 

Jim

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Cool project.

I don't know CAN at all, so I can't say if you can implement it in 16kB.

I'm currently working on a small IPv6 stack for the Launchpad (MSP430G2553 as target), and I use a SPI SRAM module in order to have enough memory. If the MCP2515 uses the same SPI mode as the SRAM module, it should be easy to use them both with one USCI module.

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One thing you guys may be able to help me with, is how to use 2 power sources and have the system automatically switch from one to the other without user intervention.

 

Have a look here:

 

http://focus.ti.com/paramsearch/docs/pa ... STRY_PGE_T

 

We use a TPS2113 to be able to power an entire Linux system (OMAP3530 based) from a backup source for 30 seconds when the main battery is removed... which to the average user seems like magic :D

 

The switch decides which power rail to use based an the sensed input voltage.

 

Cheers

TomKraut

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There is a chip from NXP that I have had my eyes on for awhile but haven't had the time to play with it. It is a Cortex-M0 MCU with embedded CAN controller and a High Speed CAN Transceiver as well as 36 GPIO. It also has the CAN drivers and CANOPEN drivers already embedded in firmware. Part number is LPC11C24FBD48/301 and the cost is under $3, quantity 1 (Avent)

 

Chip webpage: http://www.nxp.com/products/microcontro ... /lpc11c00/

 

There is also a low cost Xpresso development board ($20 at Future Electronics, $29 at Digikey) available.

 

So many great chips, so little time..... :cry:

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Here is the board, with the top user interface completed somewhat as a sample layout.

 

main.brd

 

Will get the Power and CAN over the weekend. The oddball connector at the end is a Male M12 CAN/DeviceNet sealed "micro" connector in case anyone is wondering.

 

Currently includes a 4x4 keypad, the OLED screen (as per Bluehash's booster), and indicator lights up top (top row for GRN, bottom for RED etc). All of the keys and LED's are going to be wired up through I2C chips as mentioned above once the top is completely done.

 

Jim

post-10240-135135547976_thumb.png

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Thanks for the screen shot.

 

You are right about its length possibly causing it to tip over, I will add some screw holes to mount standoffs to if not used in a enclosure, otherwise, if you installed it in a Hammond 1455C case, you'd have to use ribbon cable and not fixed headers, but you'd be able to slide it into slots that will hold the PCBs both length wise completely, and still leave you with a 20x20x41mm space for a battery pack if required.

 

Jim

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