Field code upgrades - how to do it?

[BrianT]

Hi all,
I need a reliable means of patching code in field portable equipment that is within email reach.

I have the MC Bootloader code installed in all units. If the field site has an older PC with real RS232 ports the MCS+ boot loader works a treat but more and more often the end user has a laptop or netbook that only has USB ports.

I have had very poor results with USB to RS232 converters and have bought 6 different brands to test with mixed results, none proving reliable. Setting the bootloader baud rate to 19,200 does not seem to help and some attempts to bootload have corrupted the boot loader code in the PIC18F4620. I don't want to have to ship a meLabs USB programmer with every unit.

How are you guys handling this problem?

Cheers
BrianT

[Dave]

BrianT , I have had real good luck with the IOGEAR usb to rs-232 converters. Especially when used with MCLoader.....

Dave Purola,
N8NTA

[aratti]

Are you using a level converter in your system (max232)?

I didn't experience any problem with USB to RS232 converter of different brands, but always using a level converter on my system.

Cheers
Al.

[BrianT]

Hi Aratti,
Yes I am using MAX232 chips for true RS-232 level and polarity. The problem with USB to RS232 converters seems to be the increased, and apparantly varying, end to end delay between the MCLoader sending a character and getting a reply.

My hope is that someone has found a tweak to MCLoader or has a rival product that is tolerant of these variable delays.

Cheers
Brian

[Dave]

BrianT, I have not had any problems with MCLoader w/ the IOGEAR USB to RS-232 converters and use them all the time here at work.. I have also used the FTDI USB to TTL converter cables in some designs to get away from using an RS-232 level convertor. They also work GREAT with MCLoader...

Dave Purola,
N8NTA

[HenrikOlsson]

Hi,
Not much help, I know but I'm using a FTDI TTL-232-5V cable without trouble. I also have a SureElectronics PIC-board which sports a CP2102 USB<->Serial chip, a ATEN UC-232 USB dongle as well a cheap one I got on EBAY and they all seem to work fine with MCLoader.

/Henrik.