Customers Performing Own Upgrades. How Hard Can It Be?

[timmers]

I want to design into future products the ability for a customer to connect their product to a PC and run a upgrade file which re-programmes the product.

Having looked at the bootloader method, I think that could work in principal, but trying to get the customer running the Microchip bootloader programme is too complicated.

Attached is my concept schematic (untested) showing how I could take over control of the serial port from the normal circuit.

The tricky part is getting a GUI to perform the actions automatically.
Is there anything I should be looking at before I commision a GUI be written. Also any suggestions on the circuit would be useful.

Thanks,
Tim.

[towlerg]

Dumb question, but why not use PIC with builtin USB and emulate a USB bootloader?

George

[timmers]

- Legacy with older products!
We use the 18F*6K22 and 18F*431 almost exclusively. If we were starting afresh, then we probably would use a built in USB port.

[towlerg]

I you want this to be user friendly I don't think CDC (serial port emulation USB) is the way to go. You will find it problematic to determine which serial port (COM1:, COM2: etc.) is connected. I don't know the devices you currently use but porting to another PIC might not be as difficult as you expect. Provided that your code uses symbolic names for the various components inside the PIC and no magic numbers it shouldn't be that tough.
Why not try a port before you burn your bridges? I'm curious, could you list precisely which PICs you use of the families you mentioned?

George

I had a quick look at the data sheets of the devices you use, do you use the Motion Feedback Module in any of your products?

[towlerg]

Sorry I can't edit my previos post.

Had a play with MAPS and I think I see your problem, the 18F*6K22 has a 12 ADC and 18F*431 has Motion Feedback Module. There are no PIC18F's with USB and Motion Feedback Module. There are however, 17 PIC18F's with 12 bit ADC and USB. If you are using the MFM then you have no choice but to go serial.

Most PC's don't have serial ports so that might help you find your emulated one. If not, you're going to have to ask the user or maybe trial and error?

George

[timmers]

We use the 18F26K22 / 46K22's because they have two serial ports and are backwards compatible with the 16F876/877 which we used to use. (albeit the analogue/digital configuration has to change)
The 18F2431 / 4431 (with motion feedback module) are used for motor control.

The MFM module tracks the quadrature counts (QC's) for position, and by using a known time interval, velocity. The Microchip velocity measuring module is a waste of space!

[xpa999]

Here's a thought. Thorsten Klose uses a MIDI interface as a serial port with a bootloader. It has several advantages: 1) cheap usb interface, less than $10 on ebay. 2) optoisolator to eliminate grounding issues between the pc and the device, 3) the MIDI interface is easy to access from the pc side.

just a thought.

[Demon]

Would epoxy on the PIC prevent someone from reading the PIC?

I remember we've had this discussion before.

Robert

[Ioannis]

Chinese read the wafer itself, by laser cutting the chip open. So, epoxy is a problem to them? I do not think so.

Happend to me before...

Ioannis