Help with a DIY FreHD

[AndyDiags]

I've build a FreHD and trying to connect it to my TRS-80 Model 1, but it's not working. Can someone with a working FreHD help?
I'm made both, the FreHD and the Model 1 adapter.

If you connect your FreHD to a power 5v power supply with the SD card inserted but without connecting the FreHD to your TRS-80, what is the behavior of the LEDs?
When I plug 5v into my FreHD, the red LED stays lit and the green LED stays off. Is this expected behavior?

If I plug my FreHD into my TRS-80 with the 5v disconnected from the FreHD, I see 2.6v on the FreHD 5v rail when I power on the TRS-80 & IE. Is this expected?
This makes me think that maybe my Model 1 adapter is not wired correctly. It would be great if someone else could check this on their FreHD.

 

[Kool65]

If you connect your FreHD to a power 5v power supply with the SD card inserted but without connecting the FreHD to your TRS-80, what is the behavior of the LEDs?
When I plug 5v into my FreHD, the red LED stays lit and the green LED stays off. Is this expected behavior?

Not connected to the computer I believe in that case the green LED should flash once and red stay off. Same with or without SD card. So you may have an issue with the freHD.

 

[Kool65]

Just saw your image, hard to tell but is there a jumper on Q1 to replace the missing transistor? Also double check your your firmware and GAL images.

 

[AndyDiags]

Thank you for the info Kool65, extremely helpful! On my first try I did get one green blink because the system wouldn't boot, but then I started troubleshooting and I accidentally replaced the GAL with a non-programmed one, and I also tried a second FreHD I assembled (the one in the above pictured), which didn't have the Q1 jumper installed. I fixed both of these issues.

I now get the 1 green LED blink when I power it on. The red light stays off.

My next issue is that the TRS-80 system won't boot with the FreHD plugged in. When I hold the BREAK key and power on the system with the FreHD plugged in, I get the below garbled screen. If I disconnect the 5v power from the FreHD but keep it connected to the IE, then the system is able to boot up correctly.

This goes back to my 2nd original question. When I connect the FreHD to the IE (via the adapter) but don't connect the FreHD to the 5v power source, what voltage is expected on the 5v plug on the FreHD? I'm seeing 2.6v, which seems suspiciously high. Can someone please check their system for comparison?


(Note this is the Japanese version, hence why it's got kana characters)

 

[Kool65]

Ok, I didn't do that test before because I have a M4 and not a M1. But anyway with the M4 I do in fact get 2.57V without power connected.

 

[AndyDiags]

Thanks for checking, mine is the same, at 2.56v. This confirmed nothing funky was going on the power rails, so I continued with additional troubleshooting, and I've made some progress! I was running the FreHD 5v from the TRS-80, but the TRS-80 hard drive manual says that the HD must be turned on before the TRS-80 and the IE. After I connected the FreHD to its own dedicated power supply and turned it on before the others, the system boots now!!

My next challenge is booting to the FreHD. I don't have the auto-boot ROM and would like to first boot from a BASIC command.

According to this post by Kyle Wadsten, a BASIC program can be used to load up the FreHD, but it's not working for me. The system just hangs like this:


George Phillips suggested the following command for diagnostic, but when I ran it, the system also just hangs:

10 OUT 197,1:FOR I=0 TO 64:PRINT INP(196);:NEXT

Anyone have any ideas what could be wrong? I'm using a 32GB SDCard formatted to FAT32, that should be fine, correct?
The FreHD green LED just blinks once. Should I expect it to stay ON at this point of me powering up the TRS-80 while connected?

 

[Kool65]

I'm using a 16GB FAT32 successfully. Haven't tried a 32GB. The card needs to have volume name, ie "FREDHD" or whatever. How long is your cable? Maybe try another cable or shorter cable. I originally had trouble with my first cable. The green LED should only blink when being accessed after the first blink.

 

[AndyDiags]

Volume already named FREHD. The cable is pretty short already, picture below.
I made my adapter based on Bill Buzbee and Larry Fosdick's instructions found here.
I triple-checked all the traces, and they seem to be asking per instructions (note the connector is upside down because I incorrectly mapped it upside down; I'll fix that in my adaptor v2).
The other adaptors I see online have a jumper. The instructions don't have the jumper; I wonder what it is for.
I am using an SD adaptor. I'll try to look around to see if I have a real SD Card laying around to see if that's the culprit.

 

[Trash-Eighty]

I am using an SD adaptor. I'll try to look around to see if I have a real SD Card laying around to see if that's the culprit.

My experience also. Some SD cards simply aren't working for the FreHD.

 

[Kool65]

This is what I'm currently using successfully. Make sure you buy your SD cards from somewhere reputable, there's a lot of fakes out there.

 

[Kool65]

Also if you haven't already tried firmware 2.13, try that it sometimes works better with some SD cards.

 

[AndyDiags]

More progress! I found a 4gb SD card and got a bit further. I re-ran the following:
10 OUT 197,1:FOR I=0 TO 64:PRINT INP(196);:NEXT
Output looks good, as per George, I should see "254 254 1..."


When I try to run the command to boot up the FreHD, the system still locks up.
10 POKE 16912,56:OUT 236,56
20 OUT 197,3:REM 1=M1, 3=M3, 4=M4/M4A, 5=M4P
30 IF INP(196)<>254 STOP
40 FOR I=0 TO 255:POKE 20480+I,INP(196):NEXT



Three things to try next on my todo list (not in any particular order)

1 - There code listed here which would list the contents of the SD card. I can run this to truly be sure that the TRS-80 can access the files on the SD.

2 - I could make a boot disk and try to boot from a floppy disk to the FreHD. I see a boot disk for the M1 listed here. I should be able to convert this to a WAV file, and then use Jürgen's bootstrap to write it to a floppy.

3 - Retest with FreHD 2.13 as suggested by Kool65

 

[Kool65]

If that screenshot is what you actually did then two things. Line 30 has an error it should be "INP" not "IMP". You did not issue "RUN" before doing the "SYSTEM", I would expect it to lock up if that is the case. I think it will work after doing this considering the first test worked. Yes or just try a boot disk.

 

[AndyDiags]

Thank you! Rookie mistake on my part. It was really late last night, but I wanted to see if I could make any progress.

HUGE PROGRESS TODAY!!

I tried the script that displays the contents of the SD card, and it worked!!

10 OUT 236,16
20 OUT 195,2:OUT 196,8:GOSUB 100
30 OUT 194,ASC("/"):OUT 194,0:GOSUB 100
40 OUT 196,9:GOSUB 100
50 A=INP(207):IF (A AND 8) = 0 THEN END
60 N$="":FOR I=1 TO INP(195):A=INP(194)
70 IF I <= 4 THEN S(4-I)=A ELSE IF I >= 10 THEN N$=N$+CHR$(A)
80 NEXT:B=0:FOR I = 0 TO 3:B=B*256+S(I):NEXT
90 PRINT N$;TAB(15);B"bytes":GOTO 40
100 A=INP(207):IF A AND 128 THEN 100
110 IF A AND 1 THEN PRINT "Error.":END
120 RETURN

Noteworthy comments about this script are that it added the character "D6" after each filename, and it doesn't show the size of larger files.



Next, I re-ran the BASIC FreHD script, however I'm still having issues with this. When I execute it, the system locks up with junk on the screen.



Lastly, I tried making a boot disk. Unfortunately, I don't have a straightforward way to write the boot disk to a floppy. I used Jürgen's script to convert the DMK to a WAV file. I've attached this audio file. I then used his bootstrap program to write the audio file to a floppy using the TRS-80.
I then reboot the system, and it was able to boot to FreHD!!!

The screen doesn't look perfect.
I'm pretty sure this is because I have the Japanese version of the TRS-80 and it has a large ROM which has different mapping. Loading any of the DOS systems also fails, as would be expected with this Japanese TRS-80 system.

The great part is now I know my FreHD is working without any issues! Thank you everyone for your help!!

 

[AndyDiags]

One more update. I noticed that the version of the FreHD loader I used was older. I found the newer version, and it looks good!

I think the challenge now will be to get a DOS image that can boot on the Japanese TRS-80.