A New Small Z180 Board at 33MMHz [message #5111] |
Mon, 03 September 2018 14:27 |
wsm
Messages: 223 Registered: February 2017 Location: AB, Canada
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Along the lines of the various "Tiny" (credit to Plasmo) boards, I've designed and tested a small Z180 board which runs CP/M. Basic details are:
- Z8S180 at 33MHz
- 512KB SRAM for code + 440KB RAMdisk (zero wait states)
- 512KB Flash for code + 496KB "disk" (one wait state)
- Two TTL, RS-232 or USB serial ports
- A daughter I/O board with hex LEDs, DIP switch, RTC, 8MB flash and SD card is in the works
There are more details <here> as I haven't gotten around to developing a Wiki page. Schematics are <here> for the TTL/RS-232 version, <here> for the USB version and <here> for the I/O board.
The V1.0 processor boards work okay as-is with either DIP RAM or without I/O expansion headers. I made a mistake (I'll admit it) and used the smaller machine-pin holes for the I/O expansion headers rather than the more common square post headers. However, modified headers (square edges rounded) will work and V1.1 boards will have the larger square post holes.
There is a limitation to the CTS/RTS flow control on ASCI 1 when using a Z8S180 or Z8L180 processor due to a Zilog errata. When using flow control, CTS from a host works as expected but RTS to the host must always be enabled which can be accomplished via a simple board modification. V1.1 boards will properly support CTS/RTS flow control on ASCI 1 regardless of processor. RTS/CTS on ASCI 0 works properly and is not affected by the Zilog errata.
Full kits will be $45US including Canada/US shipping but excluding a +5V power supply for non-USB boards. Full M80 source for the BIOS and CP/M is available.
I currently have some extra V1.0 bare boards available for $10US including shipping. A pre-programmed 45ns flash chip is an extra $5.
Let me know if anyone is interested in one of these boards or kits. I'll need to know:
- TTL/RS-232 or USB-only board and bare board versus full kit?
- Is a V1.0 board or kit (with modified headers) acceptable?
- For the TTL/RS-232 board kit, do you want the four SMD devices pre-soldered at no cost?
- For the USB board kit, do you want the 13 SMD devices pre-soldered ($20 extra)?
- Would you prefer a fully assembled and tested board?
At this time I'm primarily wanting to know if there's any interest in these boards or kits. I'm waiting for a shipment of additional processors (only one extra on hand) so full kits won't be available for a couple of weeks. Only three TTL/RS232 and four USB-only full kits (V1.0) will be available initially and V1.1 board/kit availability will depend upon demand.
For those that may want a much more flexible Z180 development system, I do have some pre-assembled and tested NYOZ base modules. There's some verbose documentation <here> that definitely needs paring down.
Bill
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Re: A New Small Z180 Board at 33MMHz [message #6562 is a reply to message #5963] |
Sat, 21 September 2019 11:40 |
wsm
Messages: 223 Registered: February 2017 Location: AB, Canada
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Senior Member |
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Following along on the "Tiny" MinZ series, I developed a cased version of it. This version is small enough that it can be hung off a PC's front USB connector using an integrated USB-A to male Mini-B adapter.
Size: 50mm x 50mm x 15mm or roughly 2" x 2" x 0.6" (Hammond 1551S case)
Features:
- USB powered
- Z8S180 at 33.333MHz or over-clocked at 36.864MHz
- 512KB Flash - 1 wait state : Boot code + 496KB flash disk
- 512KB or 1MB SRAM - 0 waits : 436KB or 948KB RAMdisk
- 256 Bytes of EEPROM
- 64 Bytes of battery backed SRAM
- Two USB serial ports with RTS/CTS handshaking at 115,200 baud
- Micro SD card with 25 MHz SPI interface
- Real Time Clock with rechargeable battery backup (~4+ months)
- A RUN (green) / HALT (red) indicator LED
- One user programmable LED
- A RESET pushbutton
The current BIOS and software is for CP/M 2.2, all of which is embedded in flash. The SD card currently supports a single 8MB CP/M partition while also retaining a FAT32 partition. Further BIOS development could include multiple CP/M partitions (i.e. "disks"), seamless FAT32 support and/or CP/M 3. In the meantime, testing on the base BIOS and utility programs (i.e. clock routines etc) continues.
The 36.864MHz over-clocked version is being tested for reliability and so far there are no issues. It's about 10% faster than the 33MHz version and will also allow for serial communication at 230,400 baud. Using ASCIIART.BAS as a benchmark, it takes just under 30 seconds at 33MHz and about 27 seconds at 36.864MHz using MBASIC 5.21.
This is probably as small as I'm going to go due to physical component sizes and my desire for two layer boards that I can hand solder with an iron. Further hardware development will probably concentrate on my more general NYOZ system and possibly an eZ80 system.
This board is *NOT* for the soldering novice: all components other than the switch are SMD, there are QFN's (one with 0.5mm pitch) and QFP's with 0.8mm pitch. Although the discrete components are 0603's, several of them are very close together. Since the original boards perform exactly as expected, no rework is planned at this time.
If there is enough interest, I might consider making a small batch of these systems.
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Re: A New Small Z180 Board at 33MMHz [message #6600 is a reply to message #6569] |
Tue, 01 October 2019 11:20 |
wsm
Messages: 223 Registered: February 2017 Location: AB, Canada
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Senior Member |
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Alan - Thanks for the compliment. I agree it's a neat little system that is definitely worthy of a banked CP/M-3 upgrade. If I get commitments for three of these, I'll build them up and test them for basically my cost: $50US for a 512KB system including source code, an 8GB SD card and shipping. I'd need to know 33 vs 36MHz and 512KB vs 1MB (+$5). I have other projects on the go but they would be in time for a Christmas present.
re: SMD soldering
I used to shy away from SMD as being too difficult and/or requiring new tools until I finally committed to giving it a serious try. I'm simply using a 40+ year-old Weller WTCPN iron with PTS7 fine tips, .015" Multicore solder and liquid flux pens. I also use an old X-ACTO X-TRA Hands magnifier, an X-ACTO knife with #11 blades and a pair of fine tweezers from an old biology kit ... that's it other than .050" solder wick for the occassional oopsie.
For me, the trick to SMD soldering is *CAREFUL* positioning, LOTS of flux and minimal solder. I use the tweezers to position the part and my other hand to hold the part in position using the flat edge/point of the X-ACTO blade. The tweezer hand is then free to add flux followed by the iron with just the smallest amount of solder on the tip.
QFN's can be done by dragging a SMALL ball of solder along the edges / pads. For QFP's, I tack opposite corners then use a "tap" technique on the pads / ends of each of the pins. The SM PLCC socket on this board is a bit of a challenge but the contacts are accessible and hand solderable.
Once a board is complete, one side at a time I flood it with flux remover then let it sit for a few seconds and finally blast it off with canned air. Isopropyl alcohol also works but not as well.
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Re: A New Small Z180 Board at 33MMHz [message #6992 is a reply to message #6991] |
Sat, 01 February 2020 14:51 |
djmartins
Messages: 40 Registered: February 2018
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Member |
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It's fine, I totally understand the confusion if you hadn't seen how I do it.
I bring it up because I find it very easy to do and often tack down a bunch of resistors
or caps at a time, solder one end, remove the putty then solder the other end.
I have looked at putting together a toaster oven deal for years and even have a Cricut
cutter I could cut the paste stencils for but I do boards for myself, not production and
it would take longer than hand soldering.
I use a flux pen to add the extra flux before placing the components.
Surface mount stuff scared me off for years until I had a project I really wanted
that required it so I used what I had around and now find it about the same as through
hole stuff.
Hope this helps someone else.
Here is a link to the cheap Harbor Freight eye loupe set that use
for this and all sorts of stuff:
https://www.harborfreight.com/5-piece-loupe-set-98722.html
Oh, and this is a cool little project!
[Updated on: Sat, 01 February 2020 15:19] Report message to a moderator
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Re: A New Small Z180 Board at 33MMHz [message #8022 is a reply to message #7334] |
Wed, 14 October 2020 10:51 |
wsm
Messages: 223 Registered: February 2017 Location: AB, Canada
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Senior Member |
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Fall cleanup is underway and I have several of these systems I'd like to sell. All prices are in US$ and include shipping in North America. Per prior posts, these are Z180 systems at 33 or 36.864MHz with zero wait RAM and running CP/M 2.2 Full BIOS source is included along with LOTS of extra CP/M stuff when an SD card is included.
MinZ V1.1 base modules - Choice of RS232 or USB: Complete kit at $45 or $60 for pre-assembled and tested. Kits have the SMD parts pre-soldered and only require through-hole soldering.
IO2 Modules: $45 fully assembled and tested but require a CR1220/1225 battery due to issues shipping lithium. Includes a 16GB uSD card but TIL311 LEDs are not included and are an extra $15.
MinZ Cased system fully assembled and tested: $90 for 512KB or $100 for 1MB (includes 16GB uSD card + USB-A to Mini-B adapter). I've sold several of these on eBay and they've been going for ~$100+ plus shipping.
PM me with any requests or questions. Unfortunately I haven't created a Wiki page for the documentation but there are links in the previous posts or I can email it if PM'd with an email address.
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