Anyone building a PICL? more PCBs available
 

If anyone fancies building a PICL (an SC/MP NIBL computer by Karen) I've just received another batch of PCBs:
https://www.vintage-radio.net/forum/...d.php?t=185066
Cheers
Phil

Re: Anyone building a PICL? more PCBs available
 

Yes please Phil, it'll be a useful platform to familiarise myself with NIBL before trying to get it to run on my MK14E !

Chris

Re: Anyone building a PICL? more PCBs available
 

PM your postal address please Chris

Re: Anyone building a PICL? more PCBs available
 

What a great video - essential viewing. Just think of the impact it would have had in 1980 if such a system had been available 8-)

Re: Anyone building a PICL? more PCBs available
 

I'd like one as well, please, if any left
Can send an extra one to Chris (or send both to me), if not sent already to save postage, and we'll sort out passing the extra one between us.

TIA
Owen

Re: Anyone building a PICL? more PCBs available
 

A few have asked about using an 877A
Tony used one in his:
https://www.vintage-radio.net/forum/...30#post1439530
But I'd suggest Mikes 18877 version if you can program them, if not I can supply preprogrammed at cost, currently £2.50+vat from RS
Its pin-for-pin so a straight swap.

Re: Anyone building a PICL? more PCBs available
 

Thanks for confirming the A suffix version works OK for this (Which all seem to be rated to run upto 20MHz, rather than having 4, 10 & 20MHz max speed versions, that the original PIC16F877 has) - Presumably with the same code as the original non-A suffix PIC16F877?

And also that the PIC16F18877 can be used - Presumably with different code?
I note that the PIC16F18877 also has 56KB of FLASH, rather than the 14KB in the 877(A), So I wondered if that might be useful for something / if the full 14KB is currently used - Microchip sometimes seem to say that the PIC16F887 can be an upgraded replacement for the PIC16F877(A). However, it only has 8KB of FLASH.

It seems you have to be careful to avoid the 'LF' (Low-Voltage) versions, as whilst you can get these rated to run upto 20MHz, their voltage rating is 1.8V-3.6V, rather than 2.3V-5.5V on the standard 'F' versions (So unlike (former)Atmel AVR ATMega's, where the low-voltage ones do work all the way to 5.5V - just can't run them at full-speed much below this).

After finding a while ago that some PIC's I wanted for a project were on a 1yr lead-time! (as many ex-Atmel ATMega's like the ATMega1284P still seem to be, in anything other than DIL40), I was concerned about availability - especially the older ones that are now 'NRND' so could be soon out of production. However major distributors like Farnell/RS/ Mouser etc do have stock of the original PIC16F877-20MHz etc version, as well as the PIC16F877A (which is actually a bit cheaper than the non-A versions. And Rapid, who don't sell the non-A version, are selling the 16F877A for very-much less).

However, to save paying min orders / high delivery costs, I had a look on a certain well-know online marketplace anf found a company in Bristol is selling both the 16F877-20 & 16F877A for the same price & under £5 each inc. delivery (no cheaper gambling on ones from China)
So I'd thought of getting one of each to try - Might be tempted to build a PIC14 MK14 emulator.

Re: Anyone building a PICL? more PCBs available
 

The 16F18877 code adds to the wonderful features introduced in Phil's PICL Version 2 Update while Karen's SC/MP emulator engine portion of the code remains practically untouched.

While the '877 or '877A uses all 8K (words) of its program memory for the SC/MP engine (4K) and the NIBL BASIC ROM image (4K), the 16F18877 comes with 32K (words) of program memory so we use an additional 8K to store an image of Page 1 and Page 2 RAM memory (see drawing below).

The serial port baud rate is 9600 bps instead of 1200 bps.

The system loads the Page 1 and Page 2 image and the Kitbug+ Monitor into RAM during power-up then presents a [C]old, [W]arm, [K]itbug+ Monitor? prompt.

A program in Page 2 will Auto-Run when you select [W]arm start, assuming you've saved the Page 1 & Page 2 image. NIBL was designed to Auto-Run a program in Page 2 if it detects that Page 2 is ROM. We simply modified a single byte in the NIBL ROM image to bypass the test when selecting a [W]arm start.

The Sense B + Reset sequence Phil introduced in his PICL Version 2 update to provide Hex load capability now presents a [L]oad HEX, [S]ave to Flash? prompt. The [S]ave option copies an image of Page 1 and Page 2 RAM to the image store in PIC Flash memory and this is the image loaded into RAM during power-up or reset.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The 16F18877 can be programmed with the new PICL 16F18877 firmware using an Arduino Nano or Uno. I can post the Arduino sketch if requested.

Cheerful regards, Mike McLaren, K8LH (Michigan, USA)

Re: Anyone building a PICL? more PCBs available
 

Can I check a sentence in the read.txt

"PICLV2_16F877.HEX
This is a file for programming the PIC 18F877 processor via a Pickit2 or similar.
It has two enhancements over Karens originl, the DLY instruction is implemented and it has an Intel hex-loader for loading programs into memory."

Then is the previous post there is a reference to 16F18877

I am slightly confused which PIC I should be looking to use for the best results ?

Re: Anyone building a PICL? more PCBs available
 

To clarify, Karens original PICL used and PIC16F877 which became harder to source, the 877A wa a bit easier to find, but then Mike did a port to the PIC16F18877 which is readily available in DIP40 and much cheaper!
Mikes 16F18877 has all the previous hexload/kitbug+/DLY enhancements plus the save/load feature - it also continues the reset-with-sense-A feature to autorun a machine code program standalone, no terminal.
If you already have an 877 fair enough but Mikes is the best option for a new PICL build :)
Cheers
Phil

Re: Anyone building a PICL? more PCBs available
 

Thanks Phil that is much clearer, I have a couple of 877's on hand which I will use initially but will look to get a 16F18877 next time I am pulling an RS order together

Re: Anyone building a PICL? more PCBs available
 

There are other considerations too, if you use an 877 or 877A then you really need NVRAM, as having Kitbug+ resident is such a bonus in the PICLv2 - I did the VCS Christmas 'Star' Challenge on the PICLv2 in SC/MP assembler through Kitbug+ https://www.youtube.com/watch?v=Rv_YLNM5ByA
I've bought quite a few of these, a highly recommended seller I use a lot;
https://www.ebay.co.uk/itm/225089480367
If you go 16F18877 then NVRAM isnt so vital as you have save/load. I can send you a preprogrammed 18877 today if you like, they're here ready to go!

Re: Anyone building a PICL? more PCBs available
 

Good ebay site - mildly annoying it did not come up in my ebay search when was looking for 48pin dil sockets earlier this week

Re: Anyone building a PICL? more PCBs available
 

I also found you could get the Ramtron FRAM IC (used on those '6264 Battery Eliminator' modules, that are £15+ but are essentially an SO28W to DIL28W adaptor + FRAM IC fitted), for rather cheaper - around £5 each for the FM16W08 SO28W one off there / from several of the usual distributors

However, Ramtron also did an FM1608-120-P(G) DIL28 version (Datasheet attached), that should be a direct fit and save having to use an SMD-adaptor. But these seem a liittle harder to obtain, and may have been discontinued, often needing to buy 10off (But can get 10off for around £25 on the bay) to get a good price.


Strangely, with the PIC16F18877's, they are an extortionate £16+ each on eBay (& Aliexpress) from China. But can get from many distributors like Farnell / Mouser etc. have both -I/P and also -E/P (Ext. temperature) ones in DIL40 for a very-reasonable around £2.50+VAT, if planning an order to these of enough for free delivery.

Re: Anyone building a PICL? more PCBs available
 

Phil - are you able to post the schematic for your PCB, I can see a number of versions on other linked threads or on your website, but cannot see one for the current PCB

Re: Anyone building a PICL? more PCBs available
 

I found Phil__G's page on it, from link to previous thread on this, here: http://www.mccrash-racing.co.uk/philg/picl/picl.htm
And specifically, the PCB construction & use document: (But that doesn't have the schematic):
http://www.mccrash-racing.co.uk/phil...doc_190821.pdf
- Although this does link to Karen Orton's original documentation which has a schematic: http://techlib.com/area_50/Readers/Karen/micro.htm#PICL

And from just assembling one of Phil__G's PCB's (Thanks Phil, for sending these to me. Only just realised it's a 4-layer board), it seems the schematic for this PCB is basically identical to the right-side half of this - with everything to the left of the LED's / Switches, replaced by 6way connector for the CH340G etc. USB-Serial interface (plus the 10uF bulk decoupling capacitor from the output of the 78L05, now increased to 22uF and now on the single +5V incoming from USB supply)

Re: Anyone building a PICL? more PCBs available
 

These look good

Re: Anyone building a PICL? more PCBs available
 

Sorry, only just spotted this. Here ya go:

Re: Anyone building a PICL? more PCBs available
 

Thanks, got the NVram in the post yesterday so hopefully will be up and running this weekend

Re: Anyone building a PICL? more PCBs available
 

and another PICL arrives, thanks Phil !