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Old 3rd Jun 2020, 9:22 pm   #21
philoupat83
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Default Re: PIC 14 Karen

No the pcb presents errors the 9v plug is upside down.
the extension plug is too far from the edge.
the ft232 module must move forward but nothing that cannot be corrected
during the confinement I could not print the pcb to scale 1 to check the placement of the components :mur:
slothie is a rock star he plays in a band called MK14 : rire1:
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Old 3rd Jun 2020, 9:29 pm   #22
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Default Re: PIC 14 Karen

I used bc547 transistors in the karen schema
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Old 4th Jun 2020, 11:49 am   #23
Karen O
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Default Re: PIC 14 Karen

Quote:
As far as I remember, the PIC14 executes code at full speed from RAM, and at half speed from ROM.
Unfortunately, my Mk14 emulation takes slightly longer to fetch instructions from ROM than from RAM. So my emulation runs slightly slower than a real life SC/MP would when executing out of SCIOS ROM. Note that it is just the instruction fetch which violates timing - the actual execution of instructions takes place at proper speed.

To be honest, you'd be hard pressed to detect this shortfall, but I was concerned about its effect on the cassette routines included in SCIOS. I tested these last year and, the cassette routines work fine on my emulation. It seems that the timing of the SCIOS cassette I/O is utterly dominated by long duration delay instructions (8F?) and the slightly longer instruction fetches are completely insignificant compared to these delays.
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Old 4th Jun 2020, 12:06 pm   #24
SiriusHardware
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Default Re: PIC 14 Karen

If you swapped out the 16F877 and put in a pin-compatible 18F452 running at 40MHz (Actually 10MHz multiplied by 4, 'PLL' clock mode), would it then be possible to re-jiggle things so that the fetch from ROM and fetch from RAM would both be at 'real' speed?

I appreciate what you're saying, that the slower fetch from 'PROM' makes no real difference in practice, just wondering?
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Old 6th Jun 2020, 7:58 pm   #25
philoupat83
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Default Re: PIC 14 Karen

hello
test pic 14 ok.
I added the led card for the input output with unh 74HC245 as karen says
all works
charging by the FTDI ok battery charge for autonomous operation.
the final pcb is corrected I do not know if I will make some at jlpcb.
but great educational project thanks Karen.
remains to be done the 3d box with the keys
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Old 18th Jun 2020, 6:03 pm   #26
SiriusHardware
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Default Re: PIC 14 Karen

Just a quick word of thanks to Phil, as I have now received one of his PIC14 PCBs via Tim, and very nice it is too.

If I could ask some questions

1) Do you have links to the two modules - serial module and power module - which are used on these PCBs?

2) I think you mentioned there were some small errors which need to be corrected, could you explain what these are?
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Old 18th Jun 2020, 7:54 pm   #27
philoupat83
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Default Re: PIC 14 Karen

hello sirius
I’m glad you like it.
TP4056 Micro USB 5V 1A Lithium Battery Charge Protection TE585 Lipo Board Charger Module.
FT232RL FTDI 3.3 V 5.5 V USB to TTL Serial Adapter Module Converter
1-error: the 9v socket is upside down
2-error: the ftdi module is too close
3-error: inter on/off too close
otherwise everything works very well enjoyed
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Old 18th Jun 2020, 9:55 pm   #28
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Default Re: PIC 14 Karen

Tim passed a board on to me too Phil, it's nice work. I like the multiple powering options.
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Old 19th Jun 2020, 9:56 pm   #29
philoupat83
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Default Re: PIC 14 Karen

hello
enjoyed this wonderful circuit
for links Chinese sites b..gg.od and other
thank you KAREN
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Old 14th Jul 2020, 8:32 pm   #30
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Default Re: PIC 14 Karen

Hello
attached the gerber and eagles files for the pcb of the KAREN pc14v2.
have fun

https://www.dropbox.com/t/KApaqorqxIaZ0jyv
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Old 14th Jul 2020, 8:32 pm   #31
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Default Re: PIC 14 Karen

I have to finish the box and the keyboard in 3d print.
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Old 14th Jul 2020, 8:45 pm   #32
Karen O
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Default Re: PIC 14 Karen

Quote:
thank you KAREN
I'm just pleased that people are getting enjoyment out of a little PIC project I embarked on while 'between jobs'. I had no idea there were so many like-minded people out there who would appreciate my work.

But Phil, your contribution to the Scrumpi is equally loved by all us SC/MP enthusiasts.

This forum must by now be the foremost resource on Mk14, Scrumpi and SC/MP in general.
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Old 14th Jul 2020, 10:02 pm   #33
philoupat83
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Default Re: PIC 14 Karen

Yes, Karen, I agree.
and there's still a lot to do with this microprocessor as soon as scrumpi 1 is over.
With Tim J would open a post for Scrumpi 2 and 3.
I'm waiting to hear back from JIM but maybe he's worried about this .... virus that's making us ..........
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Old 22nd Jul 2020, 1:05 am   #34
George60
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Default Re: PIC 14 Karen

Hi Everyone,

I'm new to this forum so please forgive me if I'm out of touch with whats been happening. I've been interested in the PIC 14 from I first found it around 5 years ago on the Karen's Corner site. A brilliant emulator that has taken me some time to get my head around the code used. Many Thanks Karen for bringing back some fond memories of my youth with the MK14.

I'm very interested in the pcb for the 876 chip, Great to see someone has had a go at making one.

I tried to use the hex uploader but found it difficult to use so I gave up.

Also had a port D problem not responding on my 877 prototype that took me months to read up on before I found the solution.

By the way has anyone found a simple solution to the key bounce problem. I tried using 10nF caps(103) on RA0-RA3 to gnd with some success, but some of my versions respond differently than others?
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Old 22nd Jul 2020, 1:54 pm   #35
Karen O
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Default Re: PIC 14 Karen

Hello George, and welcome to the forum.

There were two longstanding bugs in my PIC14 - an error in the way jump offsets are computed, and a port D/E initialisation problem which you alluded to.

SC/MP jump instructions do not partake of extension register offsets for operands of value 0x80. It is amazing how little problem this caused - it wasn't until someone tried to use a different version of SCIOS that the error was revealed.

These errors have been corrected now.

As for the key bounce problem, I can't say I've noticed that one...
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Old 22nd Jul 2020, 5:09 pm   #36
philoupat83
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Default Re: PIC 14 Karen

hello
thanks karen for these precisions. for the rebounds I have no problem on the two versions while on the first one I didn't put a capacitor the second one yes the transistors I used are different from the initial plan.
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Old 22nd Jul 2020, 5:45 pm   #37
Karen O
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Default Re: PIC 14 Karen

Thanks for reminding me Phil,

There is a hardware bug: 'speed-up' capacitors (10nF) can be added across each of the transistor base resistors (1k). This reduces ghosting on the display. Ideally we need a fast, open drain, high current octal inverter! The nearest I've found is a 74AC240, but of course it's not open drain, which can cause a problem if more than one key is pressed.
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Old 22nd Jul 2020, 10:37 pm   #38
SiriusHardware
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Default Re: PIC 14 Karen

I used a 74AC240 in my original build of the PIC14 and rightly enough it does cause problems if more than one key is pressed although there is actually no pre-existing monitor or software which requires you to do that.

I did plan to insert Schottky diodes in the relevant lines to the keypad so that they would not try to drive each other into opposing states if two keys were pressed, but of course I never got around to that.

Anyone building one from scratch now should probably build the 'MK3' version with discrete transistor column drivers with bypass capacitors added to the base series resistors, as per Karen's final version and as provided for by Phil on his current PIC14 PCBs.
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Old 23rd Jul 2020, 8:13 am   #39
Karen O
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Default Re: PIC 14 Karen

Quote:
I did plan to insert Schottky diodes in the relevant lines to the keypad so that they would not try to drive each other into opposing states if two keys were pressed, but of course I never got around to that.
Ooh, that's a good idea!
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Old 23rd Jul 2020, 5:04 pm   #40
George60
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Default Re: PIC 14 Karen

Hi Karen,

Thanks for the bug update.

Is it possible its the buttons I'm using, but I get multiple hits from the keyboard when typing which can be very frustrating when writing code by hand.

I noticed in your code that any instruction that uses goto Pad2 or just goto exec won't respond to the mk14 reset key. I found this out when adding my own instructions for port I/O and TRIS settings. I was testing one of my new instructions H'4C' for Tris settings on port c using code C40F4C90FE. I used the simple jump 90FE so I could view the outcome on the display and then reset to go back to monitor control. I was surprised to find that the scmp reset didn't work so I had to use the pick reset to get back control. I then changed all Goto Pad2's to Pad3's so it included the scmp button test.
I'm not too concerned about microcycle timing accuracy. I'm more about getting the most out of the PIC chip itself.
Do you think anyone in the forum would be interested in some of the upgrades I have made over the past few years?
1. Added keystroke uploaded using transistors instead of optocouplers and an ardhino nano with a TV remote control to choose the program to upload.
2. Added two new subroutines, one that reads one of the unused 14 pages of program memory H'1200' - H'1FFF' and updates ram with it using both reset keys and number keys to control which page gets uploaded.
3 The other subroutine writes a copy of ram back to one of the 14 pages of program memory using the keyboard. Its like a micro hard drive for the mk14.

4. Added new instructuons to scmp iset to control the Tris and I/O for all ports on the PIC. This gets the PIC 14 closer to the mk14 with the extra I/O chip on board that i programmed back then, but with the benefit of utilising what the pic specialises in, ports.

Let me know if any of these have been done before. I'd be keen to see how others did it.

George
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