Can't Auto-Run TURMON

Discuss construction, troubleshooting, and operation of the Altair 8800c computer

Can't Auto-Run TURMON

Postby toml_12953 » April 27th, 2019, 4:03 pm

I have TURMON at location FD00 in ROM on the FDC+
I can examine FD00 and execute it fine manually and get a dot prompt.

I'm trying to set VDIP #2 to FD so when I power up, the computer will execute TURMON.

When I set the FP VDIP #2 to FD (the MSB of the Power-On Jump Address), though, all I get on the terminal is a weird ASCII character (it varies)
and not the dot prompt. I can't type anything.

I have VDIP #1 set to 01100000 to turn on the FF Latch and Code Injection but when I set the MSB of the Power-On jump Address in FDIP #2 and save it, bit 7 (Pwr Reset) of VDIP #1 is automatically set. Is that supposed to happen?

In any case, should I be able to run TURMON at power-up? If so, how?
toml_12953
 
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Re: Can't Auto-Run TURMON

Postby AltairClone » April 27th, 2019, 7:33 pm

1) Make sure you don’t have auto-jump enabled on the front panel and on the 2SIOJP at the same time.

2) Be sure the PROM on the 2SIOJP board is disabled. Not just auto-disable, but that the switch is set to disable the PROM.

3) Yes, enabling auto jump on the front panel forces the automatic reset option. If a good reset isn’t performed, the 8080 is in an invalid state and won’t run properly,

Mike
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Re: Can't Auto-Run TURMON <SOLVED>

Postby toml_12953 » April 28th, 2019, 12:03 am

AltairClone wrote:1) Make sure you don’t have auto-jump enabled on the front panel and on the 2SIOJP at the same time.

2) Be sure the PROM on the 2SIOJP board is disabled. Not just auto-disable, but that the switch is set to disable the PROM.

3) Yes, enabling auto jump on the front panel forces the automatic reset option. If a good reset isn’t performed, the 8080 is in an invalid state and won’t run properly,

Mike


Thanks for taking time to answer! It works now. The problem was that I still had the power-on reset jumpers on A16 on both 2SIOJP cards. The front panel and both cards were trying to reset the system at power-on. Three resets for the price of one?

After removing the jumpers from A16 on both 2SIOJP cards, the computer now correctly jumps to the address in VDIP#2 at power-on.

Once again, it was just a matter of something I overlooked.

BTW, The version number shown in location 0 after right-Aux and Examine are raised is 00001000 (version 8?) Is that the latest?

Tom L
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Re: Can't Auto-Run TURMON

Postby AltairClone » April 28th, 2019, 7:41 am

The version number is displayed as two octal digits with a decimal point between the digits. The 08h you’re seeing is actually version “1.0” in octal. Version 1.0 is still the most recent version.

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