--
You received this message because you are subscribed to a topic in the Google Groups "PAL 6502 computer" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/pal6502/KPfvKGdgOcQ/unsubscribe.
To unsubscribe from this group and all its topics, send an email to pal6502+u...@googlegroups.com.
--
You received this message because you are subscribed to the Google Groups "PAL 6502 computer" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pal6502+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/a0454039-a0db-439f-b0ea-1074198722f5n%40googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/6f62b0ed-afdc-4f73-a659-882efe7cf33en%40googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/51f19e02-674c-4ccc-96a3-860758e2b354n%40googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/c167d364-58e5-4ad9-989c-841c8e03808cn%40googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/c167d364-58e5-4ad9-989c-841c8e03808cn%40googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/51ee58dc-381a-4c5d-b369-276d5abedcb4n%40googlegroups.com.
You received this message because you are subscribed to a topic in the Google Groups "PAL 6502 computer" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/pal6502/KPfvKGdgOcQ/unsubscribe.
To unsubscribe from this group and all its topics, send an email to pal6502+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/006b8b19-4ac9-4ced-acdb-c0a3c476f6fb%40Spark.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/CANf3X5WAFooF%2BgCa-xkaynM5D_JuN21njZJGZcGEWbdQvCdf4g%40mail.gmail.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/80906ffc-c8ca-4e53-8561-82e20bc352f7n%40googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/75f0c363-ab7e-4719-80f2-5730cc84a5ban%40googlegroups.com.
Patching the ROM is an excellent idea! Indeed, I patch the ROM to replace the bit banging serial port (In fact I replaced it with a 6850 ACIA emulation!)
Since the LEDs now light, means the
SCAND routine succeeds in outputting to a working 74LS145. All transistors are
fine, LEDs are fine.
What is not working is reading the keyboard or serial, which means the inputs
of the RIOT are not seeing inputs.
And the same goes for the TTYin detection at PA7?
So it could be a mismatch between the 74xx IC's and the RIOTs at the analog
level.
Like I told before, Bob Corsham had this problem in his KIM clone with 74LS145 and replacing with 74HCT145 fixed it)
Pairing NMOS with TTL can be tricky, are the thresholds of 0 and 1 reached?
It would be interesting to see measurements of the ANALOG voltages (not LOGIC!) with a scope of:
- power supply voltage at the IC's itself (especially U11 and U1 and U7
- outputs O0 -O3 of the 145 (pulses)
- PA0 when TTY jumper installed (puls)
- PA0 - PA6 when pressing a key on the keypad (note that the quick scanning means it will be pulses)
- PA7 when serial input is arriving (that is pin 11 of the 74LS00 U11)
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/40b26b04-1b8d-41e0-87d8-4d37e37ee138n%40googlegroups.com.
That's fantastic news, Hans!
I'm very happy for you but I'm also sad that the adventure is over XD
These Rockwell 6532's you've bought seem rebadged... Anyway, don't do the acetone test to discover they are good old UM6532's!
Best Regards From Brazil,
Ronny
PS: It seems my posts are being deleted, like Hans Otten's...
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/6f65f7f7-654c-481e-91f4-0451bfc7f7cdn%40googlegroups.com.
Congrats, Hans, on getting the board up and running!As Ronny mentioned earlier, it is almost sad that the quest is over, I've been following this quite closely and learned a few things. Your meticulous analysis of where the board gets stuck also made me realize how valuable scoping out an ailing board can be, especially if you know how to translate that back to the ROM code. Since most of the time I only half-know what I'm doing 16 channels will not be enough for me so decide to make the plunge and bought myself a (relatively cheap) 32-channel logic analyzer. I think I'm going to dump the entire startup sequence of the PAL-1 somewhere, in time, when I figure out what I'm doing, which may be useful for others that are troubleshooting.So, again, thanks for posting! And I'm looking forward to any further insights into this potential conflict of different generations of logic.Cheers,Hendrik-Jan
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/cc0f626c-b3dc-4aad-b78d-40cf033c96abn%40googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/73b3562b-62f7-4722-baac-b631b8f8dd53n%40googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/d6eacdbc-93e5-4433-85cc-e43a644c0037n%40googlegroups.com.
--
You received this message because you are subscribed to the Google Groups "PAL 6502 computer" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pal6502+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/CANf3X5UQUNR9EA62OEE1znfyM0qeoJePFAZAMJVRr9NQQB%3DdYQ%40mail.gmail.com.
One of the main problems, that I see, that I am having with my friend’s KIM-1 is that it looks like K5 is not working. I also noticed a lot of activity on K6, which should not be there.
This could be to a faulty U4 74LS145.
I guess my question would be, can I piggy back a 74LS145, or do I just have to go for it and remove and replace it, to find out if that is the bad component?
--
You received this message because you are subscribed to the Google Groups "PAL 6502 computer" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pal6502+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/8b8a7b7c-06ec-4116-a62c-43b938113275n%40googlegroups.com.
Piggy back will not work. Remove and replace (in IC socket this time).
My best experiences are : remove by cutting of the pins of the IC, and then solder out one by one the remains. Then insert new socket.
Do not overheat, do not pull to hard on the remains to keep PCB lines intact. Solder wick will help to open the holes.
Hans
To view this discussion on the web visit https://groups.google.com/d/msgid/pal6502/75f3857f-f0de-47f1-890b-8541b5183a07n%40googlegroups.com.