LPC MicrocontrollersのトピックRe: ISP syncronization impossible at 115200bps

ISP syncronization impossible at 115200bps

lpcware — Wed, 15 Jun 2016 17:20:24 GMT

Content originally posted in LPCWare by giusloq on Wed Jul 22 06:58:17 MST 2015
I have a LPC1778 and I'm trying to use the ISP for programming through serial port.

I can program the Flash correctly at 57600bps, but it is impossible at 115200bps. When I send sync char ('?'), I receive back from the MCU strange bytes and the the "Syncronized" ASCII word.

Another question. Why must I send the oscillator frequency to the MCU during sync sequence? I think the MCU knows very well its "default" oscillator frequency at startup and during ISP (12MHz for LPC1778).

Re: ISP syncronization impossible at 115200bps

lpcware — Wed, 15 Jun 2016 17:20:25 GMT

Content originally posted in LPCWare by R2D2 on Wed Jul 22 07:05:39 MST 2015

Quote: giusloq
I can program the Flash correctly at 57600bps, but it is impossible at 115200bps.

See: https://www.lpcware.com/content/forum/lpc1788-isp-autoboaud-issue

Re: ISP syncronization impossible at 115200bps

lpcware — Wed, 15 Jun 2016 17:20:25 GMT

Content originally posted in LPCWare by MikeSimmonds on Wed Jul 22 07:59:21 MST 2015
The boot code may be generic for several members of the 17xx family.
The ISP/IAP needs to know the clock speed in order to time the flash erase/program cycles correctly.

Mike.

Re: ISP syncronization impossible at 115200bps

lpcware — Wed, 15 Jun 2016 17:20:26 GMT

Content originally posted in LPCWare by MikeSimmonds on Wed Jul 22 08:05:17 MST 2015
The 57600 max ISP autobaud is a well known issue and mentioned in the errata sheets. You do read those don't you!

If you want to be a bit clever about it, you can always autobaud to 57600 and [@57600] issue a baud rate change to 115200 command
and change your host's speed at that point to 115200.

I think the reply to the "B"? command is at the old rate, but you can check the manual or just try it out.

There is a least one thread I saw where someone did just that.

Cheers, Mike.

Edit: Not quite the same thing, but the link in R2D2's post above is probably what I was thinking of.

Re: ISP syncronization impossible at 115200bps

lpcware — Wed, 15 Jun 2016 17:20:26 GMT

Content originally posted in LPCWare by giusloq on Wed Jul 22 23:47:40 MST 2015

Quote:
The 57600 max ISP autobaud is a well known issue and mentioned in the errata sheets. You do read those don't you!

Does revision F solve this issue?

Re: ISP syncronization impossible at 115200bps

lpcware — Wed, 15 Jun 2016 17:20:27 GMT

Content originally posted in LPCWare by MikeSimmonds on Thu Jul 23 09:50:09 MST 2015
Read the latest errata to find out!
Why ask somedoby else to do it for you?

Re: ISP syncronization impossible at 115200bps

lpcware — Wed, 15 Jun 2016 17:20:28 GMT

Content originally posted in LPCWare by giusloq on Fri Jul 24 00:12:08 MST 2015

Quote:
Read the latest errata to find out!
Why ask somedoby else to do it for you?

I already read the latest errata. I understand revision F isn't affected by this issue, but it's not 100% clear for me. This is why I asked to the community.

Re: ISP syncronization impossible at 115200bps

lpcware — Wed, 15 Jun 2016 17:20:28 GMT

Content originally posted in LPCWare by MikeSimmonds on Fri Jul 24 01:17:39 MST 2015
Did you also read that revision "F" only applies to the 144 QFP device.
This may or may not matter to you because you didn't say exactly which chip you use.
I would certainly make the assumption that the "F" revision has fixed the issue; but, like yourself, that is only an assumption.

If you need more qualified advice, I'd suggest opening a case with NXP tech support.

Mike.

EDIT: And also, when you purchase chips, there is no guarantee which revision your supplier will ship.
So you 'should' plan for the worst case and deal/live with the issue as you see fit.