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Cheapo IDE interface problems

Al Hartman

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I hope swapping that chip fixes your problem. I'm pretty sure it will.

I DID ask you a week ago if you had the right kind of chip there. Because from reading the development thread, the type of chip there is crucial to the timing of the circuit.

I'm glad you found the problem.
 

JonB

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Hi Al

Yes, you did, but as I said at the time, I assumed the kit as supplied would have the correct components.

Hmm, assumption. Mother of all **** ups, as they say.

:)

Now this may not be the only problem. We shall see....
 

Chromedome45

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Want to borrow a known good card? Not the prototype though I consider it to fragile. If a wire broke off would have a hell of a time trying to figure out where it went. Let me know by PM. I realize your are in the UK. I think.
 

JonB

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Thanks Frank. James is going to send me a new ACT part to try so let's see how that goes first.

You're right, I'm in the jolly old U of K.. ;)
 

Chromedome45

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A couple of our NFL teams played in London yesterday. Miami and Oakland and Miami won. So being from Florida you can guess who I was routing for!
I know folks way off topic...Sorry to deviate. Let me know how it goes with the replacement part.
 

JonB

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This evening I received a replacement chip from lo-tech. It is a 74ACT245.

I swapped out the HCT component and booted up.

The TEST.COM gives the same result - 80 on the register test then locks at first sector.

I tried an alternative boot image that FireBox kindly sent me with CPMFIX and HDRS10M commands. I issued the following after bootup

A>CPMFIX
A0>HDRS10M H=ABCD F=EFGH INIT

The formatting program warns about formatting a hard drive then on pressing Y to the "are you sure" prompt, it locks up at track 0000 just like TEST.COM does.

I do not know what to do now.

:(
 
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Chromedome45

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As I suspected. I have used LS245 and HCT245 and both work fine. Something is a miss. Just not sure without seeing the board. Send some close up Hi-Res pics of the bottom and top. Might help us out.
 

Al Hartman

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What are you using as your "Hard Drive?"

I'm using an 8gb CF card with an adapter. It turns out that I have to supply power directly to the adapter. The power coming through on pin 20 is not enough. I don't want to modify the adapter, so I ordered the power connector (the ones I had here had wires too short) and I'll solder in the cable to the Lo-Tech card. Hopefully, that will solve my problem.
 

JonB

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DaneElec 512 CF
SanDisk Ultra II CF
Kingston 16GB CF

I did previously try with a real hard drive too (independently powered).

I've tested the power lines on the CF card socket, they are showing voltage (see my earlier posts), and I have also checked as many signal lines as possible (again, see my earlier posts). The card adapter 's 4 pin power plug is connected to the screw terminals.

I'm wondering if it is the way I'm powering it. Connected to a USB port on my PC. Maybe it's not getting enough current. Surely it doesn't need more than 50mA.
 

pearce_jj

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The current for the EXTIOSEL line alone is 33mA, plus up to 50mA for the CF card (per specification), plus a few more mA for the other chips.

Try a mini USB charger or another 5V supply. Or maybe the external interface on the TRS80 itself is not functioning properly?
 

pearce_jj

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With test.com running...

What does this utility do? From the observed signals, it looks that nothing is ever being written to the device:

IOWR is high (U3 Pin 6)

IDE works by commands being provided by writing to device registers (i.e. ports), then waiting for the drive to set a ready flag (in which time the status register is polled, i.e. read from repeatedly), and then data read (or writing) by reading from (or writing to) the data port. It's possible that test.com is simply sitting there waiting for the ready flag to be set forever, *however* the device should assert /DASP (and so turn on the activity LED) until the command has been completed. That the LED is not lit implies that the command was never received.

Might be worth checking continuity between U3 pin 5 (/OUT) and the TRS-80 end of the cable (pin 35).

I really hope this and/or power helps!
 

Chromedome45

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I power my cheapo through the 4 pin 3.5 floppy style connector on the CF Adapter. Works fine. Power gets sent from pin 20 on the CF back to the boards 5V Line.
 

ldkraemer

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JonB,
I just looked at my Model 4 and the 50 Pin connector has 2 thru 50 (GND) facing towards the back of the Model 4.
That makes Pin 1 facing the Front of the computer and Pin 1 is the one further away from the Power Cord.
Another thing you should verify is that Pin 1 is the same on the 50 Conductor cable, because some of the
Connectors are made different and if you used two different brands of Connectors for the ends of the cable
that can switch the signals. So, verify at least four pins on both ends of the cable are correct.

The Model 4 Schematic has RP3 shown as being used for a PULLUP resistor, but my Board does not have RP3 installed
for that 50 Pin connector.

I've had problems where a PULLUP resistor did not PULLUP the Line because of a bad Solder connection.

The other PULLUP resistors you might want to check are:

U73 = 74LS645/245 has:

U73 RP3 Address I/O Connector Pin
Pin 11 - 2 XD0 1
Pin 12 - 3 XD1 3
Pin 13 - 4 XD2 5
Pin 14 - 5 XD3 7
Pin 15 - 6 XD4 9
Pin 16 - 7 XD5 11
Pin 17 - 8 XD6 13
Pin 18 - 9 XD7 15

Pin 39 - R55 XIOBUSINT 39 is PULLED to +5VDC
Pin 41 - R55 XIOBUSWAIT 41 is PULLED to +5VDC
Pin 43 - R51 EXTIOSEL 43 is PULLED to +5VDC

And finally you might want to check the Chip enables (LOW) for U73, U74, & U75

If the Chip Enables are all working properly, and the Address lines aren't stuck, due to a Buffer IC,
I'd think it should work.

If you have TASMON or HTASMON you could execute it and write HEX Bytes to that Address, in a loop,
and chase the signals to the 50 Pin Connector with a O'Scope.

Larry
 
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FireBox

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Jan 25, 2012
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Northwest
Here are some photos of my setup that I thought might help the discussion. I have it setup to plug into the back of a model 4p.

20141008_161356262_iOS.jpg

20141008_161403951_iOS.jpg

20141008_161421888_iOS.jpg

20141008_161508915_iOS.jpg

20141008_161548267_iOS.jpg
 

JonB

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Can't see much difference save that your setup is using a 5v/12v supply. Mine's very similar but I am using the USB plug for power. Even with an iPad adapter (more than 1A) it refuses to work.

I see you are supplying 12v and 5v to the card adapter, could that be it? I thought it only needed the 5v supply. I just tried with a PC power supply but it is still not working.

Don't forget, I am still getting 80 on the register check.
 
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