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I have a Small Quandry about the Lo-tech TRS-80 Ide

A

Audronic

Experienced Member
Joined
May 23, 2013
Messages
429
Location
Williamstown Victoria Australia
I have a Small Quandry about the Lo-tech TRS-80 Ide

I have 2 Model 4P's and a Model 4

If i setup the Lo-tech TRS-80 Ide for the Following :-

HD0 404 cylinders 1 Head (LSDos 6.3.1)
HD1 404 Cylinders 3 Heads (LSDos 6.3.1)

HD2 404 Cylinders 2 Heads (LDos 5.3.1)
HD3 404 Cylinders 2 Heads (Ldos 5.3.1)

This setup works Perfectly using a Real IDE Hard drive.
On the 2 4Ps and the Model 4

That was the Good news.

If i use the IDE to CF Card adapter (3 different types tried)
and set it up on the MODEL 4 they all work perfectly on the Model 4.

BUT if i now put the Lo-tech TRS-80 Ide with the CF card on either MODEL 4P's

I get This on the screen and the computer's Lockup.

Model 4p's only

http://www.vintage-computer.com/vcforum/attachment.php?attachmentid=21100&d=1413957290&thumb=1&stc=1

I have borrowed another Lo-tech TRS-80 Ide unit from Ian Mavric
and this also does the same.?

I am mildy confused as to why. ::}}

Do you have any thoughts
 

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Interesting problem! Please can you provide a little more detail over what produces this - is it immediately on power-on, after/during POST, on OS Boot, or on access to the device perhaps? And, does the port configuration of the board have any impact?
 
Hi Ray

Does it happen if you change to the other address range (0x40 rather than 0xC0)?

If you use your logic analyzer do you see any difference in the behaviour of U2 (74HCT245) pins 1 and 19 between the 4 and 4P when they power up? I am thinking it is more a 4/4P difference that is allowing the CF card to load the Data Bus during power up. To do this U2 and /EXTIOSEL needs to be activated.

JAQ
 
@pearce_jj
I start the procedure like this.
1) Turn on Ide Drive (with CF adapter)
2) Turn on Model 4p's
as the screen comes up I get the A:A:A: Screen

i have Not tried the other port confiuration.
I had a look at the Circuit and wondered about C6 (Not fitted) 50 pf.

Will test tomorrow.

Thanks

Ray
 
Last edited:
I had exact the same problem.

It only happens when the CF-card is empty or there is a not readable harddisk image on the card.
The response of a CF interface is much faster then from a real harddisk.
Probably there is a timing problem in the bios.

I solved the problem in the following way.
I use a floppy with an image of a clean LSDOS 6.3.1., without any sysgen.
Put the floppy in drive 0 and reset with F2 pressed.
The computer boots now without any problem into DOS.
After setup a harddisk of the CF card, the next time the computer boots normal.

I hope it helps

Hans 01.
 
Small error.

Please read SD-Card instead of CF-Card.
I must have been far away with my thoughts. :)

Hans01
 
Hans, do you have the SD card adapter in question to hand - is it by chance based on the FC1306T chip?
 
Indeed it is based on the FC1306T chip.

It runs very fast on both port address ranges.
No errors no problems.

Hans01
 
Thanks for confirming. That chip is actually an SD to CompactFlash bridge - hence the results being consistent with the CompactFlash is to be expected.

My guess is that your solution will work, hopefully Ray will be able to confirm!
 
pearce_jj said:
Interesting problem! Please can you provide a little more detail over what produces this - is it immediately on power-on, after/during POST, on OS Boot, or on access to the device perhaps? And, does the port configuration of the board have any impact?
Click to expand...

@ pearce_jj

"" Does the port configuration of the board have any impact ? ""

If i change the link to 40h - 47h
Yes The A:A:A:A: does not appear and the machine Boots with a non sysgened floppy.

I have added the 50 pf to C6 Made no difference, If i change the link back i still get the A:A:A:A: on the screen
and the machine locks up with the CF Card adapter.

Ray
 
Hans01 said:
I had exact the same problem.

It only happens when the CF-card is empty or there is a not readable harddisk image on the card.
The response of a CF interface is much faster then from a real harddisk.
Probably there is a timing problem in the bios.

I solved the problem in the following way.
I use a floppy with an image of a clean LSDOS 6.3.1., without any sysgen.
Put the floppy in drive 0 and reset with F2 pressed.
The computer boots now without any problem into DOS.
After setup a harddisk of the CF card, the next time the computer boots normal.

I hope it helps

Hans 01.
Click to expand...

@ Hans Welcome back

The problem is that if i have a system on the CF card or not I still get the A:A:A:A: on the screen, On the 4P's But not on the Model 4
so i cannot even attempt to setup the CF card as the machine has locked up ??

Thanks
Ray
 
jaquinn said:
Hi Ray

Does it happen if you change to the other address range (0x40 rather than 0xC0)?

If you use your logic analyzer do you see any difference in the behaviour of U2 (74HCT245) pins 1 and 19 between the 4 and 4P when they power up? I am thinking it is more a 4/4P difference that is allowing the CF card to load the Data Bus during power up. To do this U2 and /EXTIOSEL needs to be activated.

JAQ
Click to expand...

@ jaquinn

If i change the link to 40h - 47h
Yes The A:A:A:A: does not appear and the machine Boots normally with a non sysgened floppy.

I will compare both machines later today. I have some commitments up until 3 Pm.

Thanks

Ray
 
@Ray

I'am glad to be back, I was missing all of you :D

Please try these steps:

Use the latest modified BIOS
Remove the portselect jumper from the IDE-interface, if ver. 2
If ver. 1 also do the hardware modification for the adapter.
Turn of the power for the ide interface, remove the SD-Card.
Boot the computer with a clean LSDOS disk and push F2 during boot
The computer should boot now.
Turn the power for the IDE-interface on, insert the SD-Card.
Setup up a new harddisk

Good luck :)

Hans01
 
Hans01 said:
@Ray

I'am glad to be back, I was missing all of you :D

Please try these steps:

Use the latest modified BIOS
Remove the portselect jumper from the IDE-interface, if ver. 2
If ver. 1 also do the hardware modification for the adapter.
Turn of the power for the ide interface, remove the SD-Card.
Boot the computer with a clean LSDOS disk and push F2 during boot
The computer should boot now.
Turn the power for the IDE-interface on, insert the SD-Card.
Setup up a new harddisk

Good luck :)

Hans01
Click to expand...

Hi Han01

I have just followed your procedure and i get up to selecting the numbers of heads and i answer 1 and the machine locks up.


Ray
 

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It seems that you cannot address the ports C8h-CFh

Are you sure, you have the newest bios ?
No problems with burning the bios ?
If you have a rev. 1 lo-tech adapter, have you modified the print ?
Do you have the newest set of drivers ?

Hans01
 
Hans01 said:
It seems that you cannot address the ports C8h-CFh

Are you sure, you have the newest bios ?
No problems with burning the bios ?
If you have a rev. 1 lo-tech adapter, have you modified the print ?
Do you have the newest set of drivers ?

Hans01
Click to expand...

Hi Hans01

The port is C8h - CFh ( used Macsmon3 in Model 3 Mode ) C0h - C7h all FF's C8h - CFh C8 - CF -->> 00 00 00 04 14 00 A4 50


Yes I have a new BootRom (Bios).
No problems burning the Eprom (Bios)
I have tried this on Revision 1 and 2 boards and 2 different model 4p's with always the same error.
( The Ide interfaces (2) work perfectly on a Model 4, without AutoBoot)
I am using hddvr6c/dct and hdform6c/cmd.

I am getting a logic analyser setup on my Mac to start some other tests for Jaq.
to check if the timing is out.

Jaq's Request :-

""" If you use your logic analyzer do you see any difference in the behaviour of U2
(74HCT245) pins 1 (*IORD) and 19 (*ADDR-SEL) between the 4 and 4P when they power up?

I am thinking it is more a 4/4P difference that is allowing the CF card to load the Data Bus during power up.

To do this U2 and /EXTIOSEL (U4 PIN 3)(74ACT241)needs to be activated.

JAQ """

I have checked back with Gazza ( Phone call and EMails) that i had setup the Ide cards to C8h to CFh.

at the moment i am at a loss.


Thanks

Ray
 
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@Ray

Reading your results, there must be an address line grounded or not connected.
Can you swap the 50 wires flatcable between the computer and the El Cheapo with a different one.

It is possible that one of the address drivers in your TRS-80 has one bad port.
Find the address lines on the 50 pins connector and check for activity with a logic probe.

Hans01
 
Could this be the 4P attempting to boot from the adapter? The idea of using ports C8h was on the basis that the 4P might be able to boot from it natively.

If it's possible to post the port scan data for both IDE and CompactFlash devices from the 4P, hopefully we can then look back at the WD1010 registers and see what difference the machine might be picking up on.
 
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