RetroBSD

Hi Pito,

That's exactly why I think this board isn't going to work the way it is. Personally I don't think the board underwent enough testing at Olimex before it was released otherwise the problem would have been seen. I'm tempted to send an email to the guys at Olimex and moan about it, just on the off chance that they offer a replacement board. I think the newer version of the board doesn't have this issue.

If I only had more time to tinker with it and jerry rig an external osc! I don't even have one I could try in my component drawers, grrr!!

Dan

Can anyone confirm later revs of the Olimex board fix that issue? I'm gonna need something cool to sit at work on my desk next to the BSD/OS tape.

Well, JMZ144 works pretty stable for me, but may be I'm just lucky.

An alternative variant is a SnadPIC MZ board.

This is the late 2014 rev A5 errata - and how to fix the oscillator issue with A5, it may help with A4 too.
Solder in the 10kohm resistor to help oscillator start ..
Also I've seen somewhere you should not use the logic pins close to oscillator pins as they can disturb the oscillator when toggled..
Errata also says you
1. cannot use ceramic resonator for primary oscillator,
2. cannot use crystal for the secondary oscillator.
PS: As the MCHP erratas are probably written by none-technical staff - the "crystal oscillator" here means "the crystal". "External clock" means "external crystal oscillator" or any other kind of an external oscillator with appropriate output level and timing..

_________________
Pukao Hats Cleaning Services Ltd.

Hi Serge,

SnadPIC board looks rather interesting as an MZ...EF device..

It would seem that flashing it and putting in a LiteBSD microSD would make a pretty simple basic LiteBSD system?

Have you tried one out [yet]?

What are you using for MZ...EF devices right now and which do you recommend? Other comments also please?

I gotta join the party.

Wiz

Hi Wiz,

Yes, I have a couple of SnadPIC boards: one with MZ processor (not EF though), and another one with MX795. Both work pretty well See the pictures below. Kernel cofiguration for LiteBSD is still under development.





--Serge

Ordered a SnadPIC MZ...EF board.

Here's hoping ethernet is simple enough to get going (a long with additional memory later on? )

You can find a kernel configuration for the SnadPIC MZ board here: https://github.com/sergev/LiteBSD/blob/master/sys/mips/conf/SNADPIC.pic32

For Ethernet, just add one line:
External memory would require more work.

LiteBSD binaries for the SnadPIC MZ board are available for download on the autobuild page: http://litebsd.org/wiki/autobuild.php

Yay!! I've finally got my HMZ144 board to run properly. It would seem that it dislikes running from a USB power source of any kind, but connect a Li Ion 500mAh battery to it and hey presto it boots and runs like a charm!

Now to design and create a motherboard with an ethernet switch and an LCD header and bluetooth for keyboard IO.

Thanks everyone for all your help and suggestions, it helped to narrow down what the issue was. I think my not so great DSO probes were loading the crystal and killing it, hence why I thought the crystal was the issue. As it happens the small mod on the board that Olimex had done was to correct for that problem as listed in the silicon errata that pito pointed out.

Good times ahead, I hope!

Dan

Is using a 3.3V -> TTL adapter for programming required? I can't get it to show up to anything via USB...would be nice if a manual existed.

It appears the MZ...EF board is slightly ... different in how it behaves. (It is very eager to operate differently connected to USB than connected to DC...such as operating as a USB HUB(!))