FreHD Power Supply and Model 4P Boot

[tempest]

I have two FreHD questions:

1. I'm currently using my FreHD with my model 4. The FreHD is powered by a cable that attaches inside the 4 which is fine, but makes it hard to swap between systems. I'd like to use it with my 4P as well, so I need an external power supply. What are the power specs for a FreHD power supply (US) and what kind of connector does it need?

2. I seem to recall the 4P having some sort of hard drive boot ability. Holding down the 4 key on boot I believe. Will this boot the FreHD? I'd like to keep the ability to boot from disk drives so I don't want an auto boot rom.

 

[AndyO]

2. I seem to recall the 4P having some sort of hard drive boot ability. Holding down the 4 key on boot I believe. Will this boot the FreHD? I'd like to keep the ability to boot from disk drives so I don't want an auto boot rom.

FreHD can autoboot a 4P, but I don't think the standard image on SD can do it. However, Ian has an image on his site that can. Scroll down http://members.iinet.net.au/~ianmav/trs80/downloads.htm
until you get to the "AUTO-BOOT FILES FOR TRS-80 MODEL 4P (Unmodified 4Ps with standard Boot ROM)", and there you'll find 3 .zip downloads. the first is standard LSDOS 6.3.1 which will give you a 4-partition 'hard-4' file. Copy that to a suitable SD card, put that in the FreHD in place of your original card, and with FreHD connected, boot the 4P. No need to touch the keyboard, because it should boot directly to the FreHD.

This is how I have mine set up, because like you, I prefer my 4P to be able to boot to floppy too.

 

[tempest]

How are you powering your FreHD?

 

[AndyO]

How are you powering your FreHD?

When I ordered the FreHD, I asked for it to be supplied with a wall-wart. I'd have preferred to power it from inside the 4P, but hadn't taken the system apart at that point, so didn't know where it might connect to.

 

[tempest]

When I ordered the FreHD, I asked for it to be supplied with a wall-wart. I'd have preferred to power it from inside the 4P, but hadn't taken the system apart at that point, so didn't know where it might connect to.

What are the specs on the power supply? I don't want to open up my 4P either.

 

[AndyO]

What are the specs on the power supply? I don't want to open up my 4P either.

It's 5 volts. Ian supplies one, with US adapter, and a cable to plug into the FreHD's power connector. I will try and remember to take a photo of mine and post it later.

 

[tempest]

It's 5 volts. Ian supplies one, with US adapter, and a cable to plug into the FreHD's power connector. I will try and remember to take a photo of mine and post it later.

Oh can I just buy one from Ian? Is there a link for that?

 

[AndyO]

Oh can I just buy one from Ian? Is there a link for that?

I don't know that he sells them separately, mine came in a bundle with the FreHD. But I'd think any adapter that outputs 5v DC at a few mA, with a power connector for the FreHD and wired with the correct polarity would do. Someone might correct me, but a USB cable with the correct wiring for the FreHD power connector would work just fine. Just a matter of getting the connector and knowing which wires!

 

[tempest]

Any instructions on how to wire up such a cable? I'm sure I have some old 5V power supplies around here, but I don't know which way to wire up the connector.

 

[TRS-Ian]

It's wired the same as the power for a 3.5in floppy disk drive, to the pin closest to the FreHD bus is 5V, the middle two pins are ground, and the last pin is 12V on a floppy drive but not connected to anything on the FreHD, so you can connect a PC AT or ATX PSU to the FreHD and it will work.

Hope this helps,

Ian.

 

[Patrick.B (TTR)]

I use my Frehd as an external unit, and it runs off am iPhone 2A adapter where I cut the phone end of the USB cable and wired red/black (power lines) to a Berger connector, the FreHD power consumption is like .5A anyways so its plenty of power.