Small Cased Z180 at 36.864MHz with CP/M 2.2, 1MB RAM, SD & RTC

[WSM]

This is a small (2" x 2" x 0.6") cased Z180 running CP/M 2.2 at 36.864MHz with 1MB zero-wait SRAM, 512KB flash, microSD card with a 25MHz SPI interface and a clock. Power is via USB which also supports the two serial ports including RTS/CTS handshaking. https://www.ebay.com/itm/184492337888

Full disclosure: This is my eBay listing and I'm the designer / builder of this system and author of the BIOS. For those that are interested, there is some more documentation <here> .

 

[whartung]

Looks nice.

Are both serial ports only manifest through the USB port?

 

[WSM]

whartung: Thanks for the compliment. Sorry for the delay in response but I've been offline for a bit with family issues.

Serial ports are only via USB on this design. One of the primary objectives was for it to be SMALL and cased. Unfortunately many connectors are quite bulky and two DE-9 connectors would be nearly the same size as this entire system.

This design is a follow-on to a prior design of mine that had the option of TTL, RS-232 or USB for the serial ports. There is some documentation on that system <here> and if you're interested, in addition to fully assembled / tested boards I also have full kits of the TTL/RS-232 system and/or the USB system, both of which have the few SMD's pre-soldered and only requiring through-hole soldering. I also have assembled and tested IO2 demo boards but no kits or bare boards since it's mostly SMD, including a CPLD, and some are fine-pitch.



The cased system in the auction was also the inspiration for a small eZ80 system (3.15" x 1.57" x 0.79"). Current status is that the hardware has been verified and I'm well along with the BIOS development.

 

[KenUnix]

Hi,

I have a Minz C 1.2 and have been trying to copy files from the included mico-sd card now on my laptop to no avail.

When attempting to do a XODEM in minicom I am getting framing errors from the Minz.

I would also like to make a backup copy of the included Minz micro-sd card.

Thanks, Ken

 

[KenUnix]

Hi again.

I have attempted to get a Micro-SD card to work properly following your procedures.

New 32GB PNY Micro-SD card.
Inserted into Minz-2.
Power up Minz.
Use @FMT.
Says OK.
Reboot Minz.
Minz see SD card.
Do a directory OK.

< other activities >

Power up Minz-c.
No long see SD-Card??

Tried with two new PNY CD-Cards same result.

Sounds like I have a lemon.

Thamks

 

[WSM]

Per the PM sent earlier, it appears there may be a power-on till access timing issue with the PNY cards. Pressing the reset button versus actual power off/on should indicate whether that is the issue.

Testing of these systems, including the one you have, has been done with a variety of SanDisk, Kingston and Adata uSD cards without seeing any issues like this. Unfortunately I didn't do any testing with PNY cards as I don't have any.

P.S. I just saw the Jan. 11 post as I normally don't look in the "Auctions" area. Either a DM or an email to the address in the documentation will get a faster response.
Re Backup of the included SD card: The included files are in the FAT32 partition that was written / checked under Windows and although I'm not a Linux user, it's my understanding that it has drivers for accessing FAT32 disks. The CP/M area of that card is formatted but contains no files.
Re Framing errors: I'm not familiar with minicom but I know that users have successfully used HyperTerm, TeraTerm and PuTTY. At 115200,8,N,1 there is a +0.5% frequency deviation but that is within what I understand to be a +/-2% tolerance and shouldn't lead to framing errors. Note that both serial ports also use RTS/CTS handshaking. Due to my testing methodology, every shipped system has had at least a 513KB file transferred successfully via HyperTerm & Xmodem.

 

[lowen]

...
Re Framing errors: I'm not familiar with minicom but I know that users have successfully used HyperTerm, TeraTerm and PuTTY. At 115200,8,N,1 there is a +0.5% frequency deviation but that is within what I understand to be a +/-2% tolerance and shouldn't lead to framing errors. Note that both serial ports also use RTS/CTS handshaking. Due to my testing methodology, every shipped system has had at least a 513KB file transferred successfully via HyperTerm & Xmodem.

I have successfully used minicom on Debian 11 with both my Min-Z and Min-eZ; hardware handshaking is a must on either.