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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 30th Jun 2020, 11:59 am   #81
dominicbeesley
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Default Re: SC/MP timing and microcode information

I dug out my PIC stuff for the first time in over 5 years and installed the latest MPLAB IDE thing - which is a lot better than I remembered it being! (I made a Nintendo to Amiga joypad converter for my daughter as her 5yo fingers struggle with a joystick).

I might poke my head into using a PIC for USB serial, if I have a device capable of it in my box-o-chips just out of curiosity. The last time I did any USB on PIC it was all quite faffy and low level. But that must have been around 2003 and I was making a custom driver on the PC end too - so things may be easier? I have no idea where to start yet but will see how I get on for time!

D
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Old 30th Jun 2020, 4:02 pm   #82
dominicbeesley
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Default Re: SC/MP timing and microcode information

I had a go this afternoon and got a bit further but I now realise where the problem with the echoed characters is coming in....interrupts time.

I have also realised that annoyingly the read relay isn't activated while a program is running so with flow control enabled I can't stop the running program!

I'll report back later.
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Old 30th Jun 2020, 6:02 pm   #83
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Default Re: SC/MP timing and microcode information

Well, I'm a 100% official idiot.

I turns out my simplistic first attempt did work, what had been staring me in the face all the time was that the echoed characters have the top bit set!

The simplistic approach only works when on a board with more than one serial port so I need to look at the options for using a cheaper Arduino, either software serial or my OTT interrupt driven stuff

I've got to go and do other stuff now but will try and post something useful up later this week.

What I propose on the flow control is to make the Arduino respect flow control unless the pending character is a ^C in which case it will either:

if the relay signal is active: send normally
if the relay signal is not active: hold the RX line low until it gets either the RELAY signal

Sound like a plan?

D
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Old 30th Jun 2020, 6:09 pm   #84
SiriusHardware
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Default Re: SC/MP timing and microcode information

As you may or may not know there is an Arduino library for software-serial I/O on any I/O pin, although I think there is a limitation that when there are two such ports only one can receive at any one time. However I don't think this applies when you use the hardware UART plus one software-serial port.
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Old 30th Jun 2020, 6:56 pm   #85
dominicbeesley
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Default Re: SC/MP timing and microcode information

Yes, I tried software serial but NIBL echoes each bit as it is received so that is out.

I've basically written my own interrupt SoftwareSerial which seems to work.

Now some questions:
- is there a good source of NIBL BASIC programs anywhere I could test against
- is there a limit on the number of characters in a NIBL BASIC line, whenever I get to character 74 NIBL just enters the line

D
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Old 30th Jun 2020, 7:35 pm   #86
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Default Re: SC/MP timing and microcode information

I wouldn't be surprised if lines we Re limited to 72 chars +CR +-LF as this was common convention in the 70s dating back to punch cards that allowed 72 chars plus an eight character sequence no.
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Old 30th Jun 2020, 8:13 pm   #87
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Default Re: SC/MP timing and microcode information

Quote:
Originally Posted by Slothie View Post
I wouldn't be surprised if lines we Re limited to 72 chars +CR +-LF as this was common convention in the 70s dating back to punch cards that allowed 72 chars plus an eight character sequence no.
Yup....

Code:
    1367/     7BB : CD 01                       ST      @1(P1)          
;PUT CHAR IN LBUF
    1368/     7BD : AA E7                       ILD     CHRNUM(P2)      ; 
INCREMENT CHRNUM
    1369/     7BF : E4 48                       XRI     72              
;IF=72,  LINE FULL
    1370/     7C1 : 9C B3                       JNZ     GETL1
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Old 30th Jun 2020, 8:23 pm   #88
Timbucus
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Default Re: SC/MP timing and microcode information

Quote:
Originally Posted by dominicbeesley View Post
- is there a good source of NIBL BASIC programs anywhere I could test against
I would suggest an interesting one for you may be the April 1979 Practical Electronics Micro-Bus (Page 47) which has one by Nick Toop of SoC which is a program to help diagnose faults on a Microcomputer Kit (the Mk14 of course).

https://worldradiohistory.com/UK/Pra...9-04-S-OCR.pdf
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Old 30th Jun 2020, 10:40 pm   #89
dominicbeesley
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Default Re: SC/MP timing and microcode information

Thanks all,

I'll keep poking around - I was hoping for a large easy to cut and paste listing but I suspect that is asking too much.

I'll have a read of that article!

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