| Title: | Atari ST, TT, & Falcon |
| Notice: | Please read note 1.0 and its replies before posting! |
| Moderator: | FUNYET::ANDERSON |
| Created: | Mon Apr 04 1988 |
| Last Modified: | Tue May 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 1433 |
| Total number of notes: | 10312 |
Can anybody give any tips on fixxing an STFM.
The problem is,the reset line is permanantly low.this line goes to most
of the chips on the board but I have eliminated everything except the
68000,the glue and the mmu.
Removing the mmu or the glue chip,allows the reset to
toggle,also removing the shifter does the same although the reset is
not connected to it.
It appears that the 68000 is asserting reset,(not pulling it down)
Does anyone know if the 68000 should be able to assert reset and under
what circumstances
Any help appreciated
Thanks Brian
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 928.1 | Hello me old mucker... | BOOZER::WATERFALL | Thu Jul 26 1990 14:13 | 9 | |
Brian
If I were you I would find a real hardware engineer to look at this
fault I do have a number if you need one.
p.s
what is the propogation of a signal down a ETHERNET cable....???
Neal
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| 928.2 | I will look at home | SICKO::PATTERSON | Engaged to a Redhead | Fri Jul 27 1990 14:21 | 14 |
> It appears that the 68000 is asserting reset,(not pulling it down)
> Does anyone know if the 68000 should be able to assert reset and under
> what circumstances
I have the spec doc on the 68000 at home and I remember seeing something
about a reset line and when it does what. I am not much of a hardware
type so I can't be sure I will understand your problem enough to help,
but I will look at home a get back to you.
It sounds like you must know a fair amount about chips, so any info
you can give me on what I'm looking for would help me find it.
Jim Patterson
(just home from 1 1/2 weeks in Italy)
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| 928.3 | The reset instruction will do it. | SICKO::PATTERSON | Engaged to a Redhead | Mon Jul 30 1990 13:53 | 23 |
> It appears that the 68000 is asserting reset,(not pulling it down)
> Does anyone know if the 68000 should be able to assert reset and under
> what circumstances
There is a reset instruction that will assert the reset line
for 124 clock cycles. I know that this instruction is in TOS on
disk and TOS 1.0.
The reset line is used bi-directionally to reset the system,
if it is asserted externally, the 68000 read the SSP from memory
location $0000000 and the PC from $00000004, set IPL to 7, turns
supervisor mode, and begin execution.
If the reset line is asserted by the 68000 using the reset
instruction, the rest of the system is supposed to reset.
There is a second line that is often mentioned with the reset,
that is the HALT line.
If you need more info, let me know what it is, and I'll look it
up.
Jim
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