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KAYPRO and KayFreHD as a hard disk module

F

Frank S

Experienced Member
Joined
Mar 31, 2013
Messages
271
Location
Germany
Hello Kaypro Users,
the first prototype for the KayFreHD module had arrived today and works fine at once.
This extended Version of the FreHD module has extra logic and connector for the use in Kaypros.
It get power over the standard Kaypro flat cable. So is no need for an extra power connection.
The first two pictures shows the use in an Kaypro 4/84. The KayFreHD module is direct connected to the J9 header on the mainboard.
The fourth picture shows the use of the KayFreHD in an Kaypro 4/83. There is no I/O connector like in the newer Kaypros.
The "J9" is then on the piggy back board, which is plugged in the Z80 socket. On the board there are bus drivers, some inverters and TTL-logic.
The second 50pin header on the KayFreHD is for the use in the TRS-80. Then you have to remove one LS04 and change the jumper setting.
If there some people who wants this board/board set, i produce a little batch of these boards. Please let me know.
Many thanks to JAQ, without his knowledge, this project wasn't ready until now.
DSC_0201.jpg DSC_0202.jpg DSC_0205.jpg DSC_0204.jpg
 
Thanks Tez.
Here is an picture from the PCB, to see the detail for jumpers.
Frank
KayFreHD_top.jpg
 
All tests succesfully done with the prototype PCB.
Also in the TRS-80 it works perfect.
The second picture shows the complete populated board.
Frank
PS.: Questions are welcome.
image0002.jpg image0001.jpg
 
Frank, I've got an original FreHD card that I haven't got around to assembling. I guess my question is similar to geneb. Can I use this for the Kaypro? ...or do I need to get a card off you? I assume I'll have all the components I need if I've already got the FreHD kit, yes? How much are your cards?

Tez
 
Yes, the original FreHD PCB is usable.
First you have to build a adapter board, which changes some pins from the Kaypro I/O connector to the FreHD module.
Five TTL inverters (LS00 or LS04) are required on the adapter board. Then a special firmware is needed for the use with the Kaypro's.
The special firmware works also with the TRS-80. A schematic and a useful layout for this adapter is attached below.
This board is enough along with the FreHD module for using with the newer Kaypro's (1/84, 2/84, 2X/84, 4/84, 4X/84, 10/84, 12X/84, Robie).
For older Kaypro's (2/83, 4/83) you have to have the Z80 piggy back adapter board too along with the EPROM modification for 2764 types.
Frank
View attachment KAYPRO_FreHD Adapter.pdf KAYPRO_FreHD Adapter_2.jpg
 
If you are using /84 machines then Frank's adaptor design is a great way to use the TRS-80 FreHD.

If you are using a 4/83 (and hopefully the 2/83 - Tez - Phil Avery is going to lend me his for testing) the approach that requires least modification to the machine is a piggy back adaptor board with both a ROM and Z80.

This is required because the ROM on the /83's is too small and doesn't have sufficient decoding on the main board to support the KayPlus firmware. Also because there is no expansion connector like the /84's.

This is the approach I took when Frank and I were working on the project (because I have a 4/83). I built a single adaptor board that plugged into the ROM and Z80 sockets. It does require two additional wires to be soldered to one other chip on the main board but is easily reversable if you want to return the machine to "stock" configuration. The connector on this adaptor allows a "TRS-80" FreHD to be used with a straight through 50 pin cable.

Some photos of the prototype board are shown below. I have done a layout for it and am waiting for some PCB's to arrive. They don't get delivered to me as quickly as to Frank.

BLOG_KP1.jpg BLOG_KP2.jpg

And you do need updated PIC firmware on the FreHD. This is still compatible with the TRS-80 but adds support for 512 and 1024 byte sectors and improved WD1002 controller compatibility.

From a functionality standpoint there is no difference between this and Frank's designs. Both will run the KayPlus firmware (Advent only on the /84's but hopefully one day we will find it for the /83's) and boot directly from the FreHD.

I hope to get a write up on the project completed and onto my blog in the next week.
 
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Hello Geneb,
depending on the interest, the board are available soon. Details follow.
Frank
 
Please let me know - I'll take at least one. I haven't used my Model 4 in years, but having a FreHD that would work with either my 4/84 or my 10 would make them a LOT more useful.

tnx.

g.
 
I'm interested in this from jaquinn.

>If you are using a 4/83 (and hopefully the 2/83 - Tez - Phil Avery is going to lend me his for testing) the approach that requires least modification to the machine is a piggy back adaptor
>board with both a ROM and Z80.

>This is required because the ROM on the /83's is too small and doesn't have sufficient decoding on the main board to support the KayPlus firmware.
>Also because there is no expansion connector like the /84's.

>This is the approach I took when Frank and I were working on the project (because I have a 4/83). I built a single adaptor board that plugged into the ROM and Z80 sockets.
>It does require two additional wires to be soldered to one other chip on the main board but is easily reversable if you want to return the machine to "stock" configuration.
>The connector on this adaptor allows a "TRS-80" FreHD to be used with a straight through 50 pin cable.​

I've got a FreHD for the TRS-80 Model 4, which I haven't yet assembled. Actually I am quite happy with my TRS-80 model 4 with floppies at the moment. Both drives work well and I tend to like my computers as original as possible.

However, on my Kaypro II, one of the drives is dicey. If I could mount the FreHD card inside (with the piggy back adapter board) and tap into internal power (maybe with the power plug that presently goes to a drive) then this is something I'd want (depending on the price of the board and components of course).

One question. Does the board on a Kaypro make the machine think it's connected to a hard disk, or two floppy drives (using floppy disk images of course). I'm just trying to ascertain that with the Kaypro II, you'd get the same experience as if both disk drives were working (or not)?

Tez
 
One question. Does the board on a Kaypro make the machine think it's connected to a hard disk, or two floppy drives (using floppy disk images of course). I'm just trying to ascertain that with the Kaypro II, you'd get the same experience as if both disk drives were working (or not)?
Click to expand...

The Kaypro sees the FreHD as a hard disk drive. It will boot from the FreHD so even if both your floppy drives fail you can still run the machine. You can configure your floppies as different drive letters depending on your preference. This is all due to the KayPlus ROM... documentation is available at http://www.microcodeconsulting.com/z80/kayplus.htm

You really should get your FreHD built for the Model 4. It will change your life (well as much as this sort of technology can). FreHD on the Model 4 connects to the external expansion connector with no mods required (unless you want autoboot) so you can keep a completely stock machine.
 
I think I need two FreHDs Andrew, one for my Kaypro II (permanently inside) and one free-standing one for the TRS-80 Model 4. Then of course there is my System 80 and Model 1 to think about (-:

Seriously though, these are wonderful devices and it's great to see the work you guys are doing for drive replacements on the old Z80 gear.

Tez
 
For all older Kaypro's (2/83, 4/83, 10(w/o modem)) you have to have a 27C64 (8Kx8 ) EPROM to use the KayFreHD.
Also for the use of the KayPlus ROM without using the Hard drive feature, you need a EPROM adapter board.
Such a board i gave in production (10 items) and it arrive in about 10 days.
The board features the use of up to an 32Kx8 EPROM/EEPROM, so up to four ROM-images can be choosen by change the jumper setting.
The EPROM socket position on the Kaypro mainboards vary in position relative to the Z80 socket, so i don't combine it with the Z80-I/O adapter board.
Depending on the mainboard there are wire connections necessary, which grabs needed signals that not available from the original EPROM socket.
On Kaypro 2/83 one wire from U60 pin 14 and two wires from U59 pin 2&5.
On Kaypro 4/83 one wire from U60 pin 14 and one wire from U59 pin 5.
On Kaypro 10(old) one wire from U48 pin 10.
Frank
EPROM_256_top.jpg KayFreHD_bot.jpg
 
I've actually tried the KayPlus ROM, but there's some kind of bug with the MOVCPM that comes with the version of CP/M I have for the 4/84 and it won't allow me to shrink the TPA in order to sysgen a KayPlus boot disk.

Can the FreHD work with the Advent Turbo ROM as well?

g.
 
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