The rise of FreHD

[rubber_jonnie]

Thanks... and good luck with your TRS80... And A5000 networking.

Cheers

[rubber_jonnie]

Well, I caved and ordered a Quinnterface...

Bit expensive but I'll take it out of next month's gadget budget as it was the last one up for sale on eBay, so I didn't want to lose it, and seemingly it's sold by IanM from TRS-80.com.

Will need to do some figuring out when I get it as it behaves like an expansion unit and adds in 32k, so expects the TRS-80 to be 16k, not 64K like mine. I may also need to revert the ROM to original, but we'll see on that one.

It also appears to incorporate the M1 Hard Disk interface I just built, so that is effectively now just something I built that will gather dust...

Won't be here until just before Christmas as it's coming from down under.

[rubber_jonnie]

Ok, so my Quinnterface is in the post, not sure how long it will take to get here, but it is at least on the way.

I spoke to the seller and he has confirmed that I will need to downgrade the M1 to 16KB before I can use the QI since it adds 32KB of RAM as well as the HDD part of the Expansion Interface box.

With an EI I can apparently revert back to 64KB internally and still use the FreHD, and that's where my M1 cable that I built earlier comes in (D'oh). I don't mind too much as long as I have a full complement of RAM.

However my ROM mods can stay, so for now I have Level II basic 1.2 & 1.3 installed and I can use either, plus it has the FreHD autoboot component installed as well, so that's all good.

I'm also 'Amped' (Get it ) for this:

PXL_20231124_125532391.jpg (147.63 KiB) Viewed 127 times

When I next have the TRS open I'll be installing this small amp and a little speaker to give the TRS a voice

[Tomswork]

I'm old school the am radio was what I used for sound on a trs-80 lots of screeching

Tom

[rubber_jonnie]

I'm old school the am radio was what I used for sound on a trs-80 lots of screeching

Tom

[rubber_jonnie]

Well the Quinnterface is leaving Australia soon I hope, it's cleared for international departure. Expected delivery according to eBay is 22nd of December, but I'm hoping it arrives sooner!!

[stephen_usher]

I'm crossing my fingers.

[rubber_jonnie]

I'm crossing my fingers.

Me too, but it'll be on here as soon as it arrives

[rubber_jonnie]

Ok, so I pulled the TRS-80 apart with the intention of 'adjusting it' (For adjusting read 'bodging') so that the RAM only reports 16K in readiness for the Quinnterface arriving (It's still in Aus apparently).

I figured that since I have already modded the mainboard to remove -5v and 12v from the RAM sockets (Originally 4116's), all I'd need to do is lift pin 9 (A7) on all the ICs, join them together and connect to either 0v or 5v and then it 'should' appear as 16K.

But having done that I still see 48KB (64KB installed) when i run a memory report and having A7 at 0v or 5v makes no difference. So, has anybody got any thoughts as my head is currently fried from work!!!

[rubber_jonnie]

So, double checking my work, to replace 4116s in a Spectrum with 4164s you have to lift pin 1 and connect to GND, pin 16, and pin 8 and connect to pin 9, since 9 is 5v for the 4116.

So that means that pin 9, A7, is connected to 5v as that is +5v on a 4116, and then pin 8, the +5v for a 4164 is connected to pin 9.

This means pin 9 for every 4164 is connected to +5v. Hopefully this is logical so far.

Pin 1 of the 4116 is -5v, which we don't want connected to the 4164, so instead it's connected to GND on pin 16. Both the 4164 and 4116 have GND on pin 16.

Now, since pin 1 of the 4164 is supposedly NC, it seems logical that there is no need to tie it to GND, but I think I have to try it since at the moment the 4164s still report as 64k.

Meh!