MiSTer FPGA Forum

In PCXT mode, with the 5160 BIOS (built by the included script this week), I have problems when rebooting with CTRL-ALT-DEL. Sometimes, I get into a state when only alternating keypresses are recognized. More commonly, I get a 101 POST error after rebooting.

I've tried this both with and without the XT-IDE bios enabled, and I get the same result. I don't have this problem with non-IBM BIOSes.

Is this "normal" right now, or am I hitting an unusual problem?

Thanks,

Michael

This issue seems to occur when a soft reset performs a reset operation on an interrupt or timer module.
Perhaps the soft reset implementation of the chip(8259 or 8253) is inappropriate.
I will investigate this when I have time.

As part of the BIOS diagnostics, there is an IMR test for the 8259A.
In that test, when IMR = 0h and Timer 0 output = H, the issue seems to occur.
In other words, the timing at which CTRL-ALT-DEL is input determines whether 101 occurs or not.

The 8259 test in the normal reset state is before Timer 0 starts counting, so no interrupt is generated even if IMR = 0h.
However, with CTRL-ALT-DEL, the issue occurs because the 8259 test is started while Timer 0 is already running.

I am currently trying to come up with a solution.
However, these solutions may affect other behaviors.
Therefore, this issue may remain for the time being.

For now, I recommend using the OSD or reset switch.

Even when 101 does not occur, I have experienced the 601 error or the keyboard not working.
These are resolved in the following branches.

https://github.com/kitune-san/PCXT_MiST ... c609d0214b

kitune-san wrote: ↑Sun Mar 12, 2023 11:21 am

I am currently trying to come up with a solution.
However, these solutions may affect other behaviors.
Therefore, this issue may remain for the time being.

kitune-san wrote: ↑Sun Mar 12, 2023 11:31 am

Even when 101 does not occur, I have experienced the 601 error or the keyboard not working.
These are resolved in the following branches.

https://github.com/kitune-san/PCXT_MiST ... c609d0214b

In addition, adding the following commits will eliminate the 101 error.
However, keyboard input during diagnostics will cause the keyboard to get stuck.

https://github.com/kitune-san/PCXT_MiST ... 00966f4b0f

Probably difficult to improve further.

kitune-san wrote: ↑Sun Mar 12, 2023 3:24 pm

In addition, adding the following commits will eliminate the 101 error.
However, keyboard input during diagnostics will cause the keyboard to get stuck.

https://github.com/kitune-san/PCXT_MiST ... 00966f4b0f

Probably difficult to improve further.

Hmmm. Sometimes the keyboard stops working. (e.g. Area5150)