WHO DOESN'T WORK WITH THE NEMOV CONTROLLER? WHO DID NOT WORK FOR?
ZXNet echo conference «hardware.zx»
From Kirill Frolov → To All 22 March 2001
Press RESET immediately, All!
If there are such people or if it didn’t work for someone, and then after
any
shamanism has earned, please test my bugfix. He helped me. Screw conner on
210mb. Without
bugfix, the driver hung, and the screw light blinked. But I can't check mine
controller on
different models of hard drive problems. The reasons for the problems I see are that
chip type
ID7 (series is not important) has outputs that are not very well suited for operation
for a long time
the hard drive loop and, as a result, a cycle of writing to registers at least
bifurcates, and
the screw command entries and the driver become out of sync, the driver hangs forever
polling cycle...
There is also a second potential bug of the scheme that I have not identified: when writing a word
to hard drive
The data in the drive is captured on the positive edge of the IOWR signal. A
register IR22 which
stores the contents of the higher half of the address bus and is also controlled by the IOWR signal.
If the hard drive
reacts to changes in the IOWR signal longer than the IR22 register turns off (plus
signal delay
in the loop), then an erroneous value will be written to the high byte of the word.
All bugs can (should!) be fixed with this bugfix:
1. Return the circuit to its original form (so that everything is like Nemo’s, otherwise it won’t have
meaning).
2. Doesn't work? This is very good!
3. RESET is applied to the screw directly, bypassing the AP5 chip.4. Instead of RESET, pass through the AP5 chip (to the same contacts)
the IOWR signal is directly from the ID7 decoder and only then goes to the others
parts of the diagram.
5. Signals HA2 and IORD passing through AP5 change places. That is, HA2
must in
As a result, go through the AP5 half controlled by the EBL signal, and IORD
through constantly
included half.
6. Turn on, test...
7. TESTING DISK WRITES ON LARGE FILES, counting CRC, not checking
Were you beaten?
It’s better to do it in iS-DOS on a partition of the hard drive that you don’t mind
accidentally ruin it!
8. We write the report in the echo, in the soap...
9. For greater reliability (and even more so if there were problems in point 7) on
OE chip input
IR22 (the one that is connected by outputs to the higher half of the data bus
screw) instead of IORW
The INVERTED signal IORD is supplied. That is, it will be necessary to pay
put 1533ЛH1 or
something similar.
10. EVERYTHING.
P.S.: There is also a very easy way to increase the data reading speed
from the hard drive to 125% of the current value - instead of A0, use the second decoder
A8.
Now reading (the original Nemov circuit) occurs like this:
INC C
INI
DEC C
INI
....
And it will happen like this:
INI
INI
....The recording speed does not change during modification. It is worth remembering that on average
read
usually many times more than written - fast reading is much more important
slow recording.
Refinement does not make sense on cars with turbo mode - speed increase
will be scanty.