ZXmore or the ZX80CORE follow-up

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
User avatar
PokeMon
Posts: 2264
Joined: Sat Sep 17, 2011 6:48 pm

Re: ZXmore or the ZX80CORE follow-up

Post by PokeMon »

Yes, of course. You don't need a diode, just set a jumper. You can connect a switch to change between PAL or NTSC, if you like.
User avatar
PokeMon
Posts: 2264
Joined: Sat Sep 17, 2011 6:48 pm

Re: ZXmore or the ZX80CORE follow-up

Post by PokeMon »

So the boards arrived right in time to just assemble one for the show in Mahlerts. Pictures and further information follow here in about one week.
There may be a spy in Mahlerts loading up pictures from the development mule a bit earlier. :lol:

As far as I could test it is running very well - not tested and implemented all features due to preparing time.
sirmorris
Posts: 2811
Joined: Thu May 08, 2008 5:45 pm

Re: ZXmore or the ZX80CORE follow-up

Post by sirmorris »

Excellent news Karl - I can't wait to see!
User avatar
PokeMon
Posts: 2264
Joined: Sat Sep 17, 2011 6:48 pm

Re: ZXmore or the ZX80CORE follow-up

Post by PokeMon »

So here are the news of the first mounted pcb of ZXmore.
Very good news - the board did run very well during the weekend at "Mahlerts" in an endurance test and there haven't been any big problems while assembling the board and powering up. Just some minor flaws which can be solved gracefully. There are two narrows which can be solved with sockets or double stacked sockets (best use precision sockets for that). I used a PLCC item from design spark library which was marked too small and there are 2 dip14 ICs which are placed a bit to near. And one pullup resistor was missing which can be added easily on the back side as SMD component (1206 or 0805). Thats all.

I am a bit sick now with a bad cold and the software rev.1 is still not finished but planned to be ready in mid of may. So delivering of boards or assembly kits will start in about 2 weeks with the first software revision. The early birds may write me a PN, I have all in all 10 full kits for the first flush. Will be listed by sellmyretro soon as well. Now some pics for you of the ZXmore. Today I was able to load a ZX81 rom from the master control image with configuration of the 2 registers/latches and missing features are now a config tool and the USB communication for loading programs from the USB stick.
IMG_8414k.JPG
IMG_8414k.JPG (187.38 KiB) Viewed 3395 times
IMG_8418k.JPG
IMG_8418k.JPG (206.11 KiB) Viewed 3395 times
IMG_8421k.jpg
IMG_8421k.jpg (124.6 KiB) Viewed 3395 times
User avatar
PokeMon
Posts: 2264
Joined: Sat Sep 17, 2011 6:48 pm

Re: ZXmore or the ZX80CORE follow-up

Post by PokeMon »

Some last changes in the bill of materials:

for a bit less brightness of the 3 color led (very useful in a debug/selftest mode as well as indicating running instance 1-7 in color blue, green, cyan, red, violet, yellow, white)

R30 = 220R (was 100R)
R31 = 330R (was 180R)
R32 = 1k (was 330R)
R33 = 680R (was 180R)

R23 = 12.7k (was 7k5) - for correct size/length of back porch - together it is better to change IC8 from 74HCT08 to 74AHCT08 as this has schmitt trigger characteristics, the 74HCT08 is swinging shortly at end of back porch due a simple r/c time constant, resulting in a possibly visible unclean border at the left picture border.

IC8 = 74AHCT08 (was 74HCT08)

Finally C7 changed from 33pF to 18pF (all 18pF can be 15pF as well) for correct load signal for the video shift register.

And R36 = 10k SMD 1206 - the missing pullup resistor for a bootloader function with empty or wrong flash rom.

Here is the complete bill of materials:
ZXmore-V11-BOM_en.pdf
(67.27 KiB) Downloaded 185 times
User avatar
1024MAK
Posts: 5103
Joined: Mon Sep 26, 2011 10:56 am
Location: Looking forward to summer in Somerset, UK...

Re: ZXmore or the ZX80CORE follow-up

Post by 1024MAK »

Hello Karl

Sorry to hear that you are not well. I wish you good luck in getting better.

I would like one full kit. I presume this is the Board kit, and the Parts kit. Does it include the Keyboard set? As I would like the Keyboard set as well.

I have sent you a message.

I'm in no rush, wait until you are feeling better ;-).

Thanks :D

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
superfo
Posts: 74
Joined: Wed Jul 08, 2009 9:12 am

Re: ZXmore or the ZX80CORE follow-up

Post by superfo »

I also want one part kit.
User avatar
PokeMon
Posts: 2264
Joined: Sat Sep 17, 2011 6:48 pm

Re: ZXmore or the ZX80CORE follow-up

Post by PokeMon »

Just to announce - the software revision one is finished and the ZXmore is ready to be delivered right after come back from my holiday around 15th of july.

The first revision supports up to seven instances with ZX80, ZX81 and compatible software/rom's and loading programs from a USB stick. All instances can be changed with simple key press and are interrupted and continued after switch back. Running them concurrently, ZX Spectrum support and save data on USB stick follows in the next revision and CP/M in the third as easy to install updates (firmware update on USB stick). During summer the two updates will be published here.

Here some pics of the first software revision.
IMG_8517k.JPG
IMG_8517k.JPG (160.53 KiB) Viewed 3259 times
IMG_8477k.JPG
IMG_8477k.JPG (151.06 KiB) Viewed 3259 times
User avatar
PokeMon
Posts: 2264
Joined: Sat Sep 17, 2011 6:48 pm

Re: ZXmore or the ZX80CORE follow-up

Post by PokeMon »

So - ZXMore is ready now to be delivered for the volunteers . :mrgreen:

The release 0.9 is stable now after fixing some problems with lost data when reading bigger programs from USB stick to load into memory. The FTDI chip is announced as very fast with read/write timing of 25ns and DMA which should provide up to 40 MByte/s. In reality it's not true DMA or with a too small buffer (feels like 16 byte or so only). I had to write my own driver for that while reading with only 1% of speed. Data is read with INIR instructions which takes 21 clock cycles or 3.2 microseconds per byte when using higher clock frequency (6.5 MHz). The maximum theoretically available speed when reading data with Z80 is 300 kByte/s but the data is read in SLOW mode with an effective speed of now 50 kByte/s in practice which is quite acceptable, I think. Could be theoretically increased up to 150kByte/s in FAST mode but there won't be much data to transfer in 48 or 56 kByte RAM.

Data is transferred in 1kByte blocks which is more or less 20ms or 1 frame when taking effective cpu time of 6.5ms and some job to do in the USB controller and the USB drive/stick. There is a latency of approx. 60-100ms and the very first access on the filesystem may take 400ms. Normally all programs should be loaded or transferred into memory right in the time you press NEWLINE or less than one second - even 16k or more. This may depend on the quality of USB stick used - these measurements are made with a very simple and cheap version. Cheap can be assumed with slow. The programs are transferred with double SHIFT-L command - not with the LOAD command which is available with EAR connector, too (just in case). Browsing in the directories are provided in the next version only as well as save of data or programs (planned in release 2 coming next month or so).

Default config is now ZX81 for instance 1-5 and ZX80 for instance 6-7 while control software resides in instance 0. ZX81 is started with 8k ROM and 56k RAM while RAMTOP is fixed to $8000 as same as with 16k RAM pack. RAMTOP may be set higher manually and can be configured as some more options in next release 2. Doesn't make too much sense to enter config with no save option. ZXmore provides a softboot feature which allows to press the reset key while other instances are kept in running state. If one instance hangs, the others won't be affected. This is the workaround now for ZX80 instances which stop the control image as they do not handle NMIs by now - this is the way to come back to control. In a later version the ZX80 image may run with NMI as well.

As soon as save data on USB stick is provided in the next release you can expect a standby mode to write all RAM of all instances to disk, switch off the ZXmore and continue work next or afternext day with reload all data from disk and restart system where it has been stopped. So this is more WIN like - not sure if this is an advantage for Z80 hardcore users. :mrgreen:

So have fun ! 8)
ZXM_Rev0.9a.jpg
ZXM_Rev0.9a.jpg (80.59 KiB) Viewed 3208 times
User avatar
PokeMon
Posts: 2264
Joined: Sat Sep 17, 2011 6:48 pm

Re: ZXmore or the ZX80CORE follow-up

Post by PokeMon »

Here is the partly changed parts list of ZXmore:
ZXmore-V11-BOM_en.pdf
(67.32 KiB) Downloaded 156 times
So the resistors for the 3-color led have been changed to less brightness due to user request in Mahlerts, the reset capacitor C5 is changed to a tantalum type which gives better reset response or more stable operation after reset and two more sockets DIP14 are needed as there are needed 2 sockets double stacked for two ICs due to mechanical reasons. Take note that I changed IC8, IC9 and IC19 from HCT to AHCT type. This was made due to timing requirements of the video generation which could result in some small needles when inverting and noninverting chars are mixed - seen very rarely and depending on quality of your TV or monitor. This is 20ns spike on video line or 1/8 pixel width - harmless and very rarely seen but not nice. The board works with HCT chips as well - first saw these needles on the screen when using the CLKFREQ.P program which use some special chars during plot scene.

So ZXmore is ready to be ordered right now for the early birds - the listing in sellmyretro may take a week or so to finish some more documentation and description. If somebody needs some special parts only please send me a PN as well as you wish to order some kit. The TO220 heatsink for the voltage regulator is now part of the board kit.


There are 3 kits I will offer officially like following (prices are in EUR and GBP, there maybe a difference but the currency exchange changes daily and paypal will charge additional fee for receiving GBP on an EUR accout):

Board kit for GBP 24.00 (EUR 30.00) including some maybe hard to get parts and SMD chip already soldered on the board
* Pcb board 204 x 156 mm, 2 layer in white color with black silk print
* VNC2-32L1B USB controller, programmed and soldered already (SMD part)
* EPM3032ALC44-10N, programmed, CPLD in PLCC44 case, can be inserted in a PLCC socket easily
* RGB LED, 4 Pin
* Reset switch MJTP-1105
* Battery holder S8411-45R (for CR1220 batteries for the RTC chip)
* TO220 heatsink

Parts kit for GBP EUR 40.00 (EUR 50.00) with all other parts (without the keyboard)
* see attached PDF for details (including high precision sockets)

Keyboard set for GBP 16.00 (EUR 20.00)
* Original ZX80 keyboard membrane in high glossy quality for high asthetic demands
* 40 Alps SMD tactile switches SKQGAFE010 for an easy and bombastic type feeling

International shipment (outside Germany)
* GBP 2.90 or EUR 3.60 for board only
* GBP 6.00 or EUR 7.60 for complete assembly kit including full insurance up to GBP 80.00 or EUR 100.00



And here to see the full assembled version with the mounted keyboard - ready to use. 8-)

Image
Attachments
IMG_8421k.jpg
IMG_8421k.jpg (124.6 KiB) Viewed 3206 times
IMG_8418k.JPG
IMG_8418k.JPG (206.11 KiB) Viewed 3206 times
Post Reply