H8 Collection

Here is a quick video going from an empty H8 chasis to a running system This demo is using the stock CPU and one of my 16K memory boards.

We start off by inserting the two boards, connecting the front-panel to the CPU, and then booting it up. From there, I keyed in the "Memory Test Routine" from the original H8 Operation Manual (which was mostly shown at 10x video speed). Finally, I ran it!

Here are a few notes about this set-up/video:

• Even though I set my phone camera shutter speed very low, there appears to be some flicker on the display. Rest-assured there is no flicker visible to the human eye. The display is rock-solid.
• If you are watching carefully, you'll notice that the keys I was pressing didn't match their function exactly. This is because the Panel Monitor ROM (444-60) on the CPU is "PAM-8 GO" which uses a particular keyboard layout. However, the key-caps on the keyboard are set-up for "PAM-37" which is on the ROM (444-140) on the Z80 CPU board.
• I cut the video during the middle of the memory test. It just gets boring watching the BC register count up. However, it runs through the entire test, and cycles back starting over at zero.

PAM-8	PAM-37
Previous key-caps (included)	New key-caps (on machine)

This is a quick video showing the installation of the H8-4 board into the H8, and demonstrating its connection to the H19. Note that the serial cable is also included in the collection.

Here are a few notes about this set-up/video:

• Even though I set my phone camera shutter speed very low, there appears to be some flicker on the display. Rest-assured there is no flicker visible to the human eye. The display is rock-solid.
• The same can be said for the H19 - its display is rock-steady once it is warmed up. There is no flicker or apparent rhythmic "brightening" that you can see in the video.

Here is the data that I entered into the panel to first configure the serial port, and then send the message.

For each line below, I pressed the MEM key to put the panel into memory address entry mode. Then I typed in the 6 numbers. The H8 panel beeps for each group of 3. Then I pressed the OUT key to send the entered data to the H8-4 board.

Panel Data	Description
200 353	Set DLAB bit to allow baud input
000 351	MSB of 9600 baud setting
014 350	LSB of 9600 baud setting
003 353	Set 8-bit words, and clear DLAB bit
017 354	Set modem control lines (like DTR)
110 350	Letter H
145 350	Letter e
154 350	Letter l (I hit the OUT key twice)
154 350	Letter l
157 350	Letter o
041 350	! (I hit the OUT key multiple times)

Note that ports 0, 1, and 2 on the H8-4 board are configured to be off. Port 3, the port I am using, was configured as 35 and interrupt 3.

We've been building up to this, a fully-loaded H8 system, runing HDOS!

In this video I install the Floppy Controller board, and two more 16K memory boards (#2 & #3).

To get up and running with HDOS, I pressed the GO key (4) which ran the code in ROM to boot from the H17. Then you could see the SPACE displayed on the panel of the H8. This is the H8 asking for the terminal to hit the space bar (twice) so that it can figure out the speed that the terminal is using.

From there, I hit ENTER on the H19 to boot the system. Then it asked for the date, and I used 36 years ago (ask me offline about that). Finally, I got the command line prompt, and did the following commands:

Command	Description
DIR	List the files on the drive #0
MOUNT SY1:	Spins-up, "mounts", drive #1
DIR SY1:	List the files on drive #1
DIR	List the files on the first drive again

Last video - and I'm sparing you the tedium of me plugging in boards.

So for this video I have replaced the 8080 CPU board with the Z80 board. I've also inserted the 4th RAM board for a total of 64K running in the machine. Note that all of the memory boards have been adjusted to start from 0x0000. Also, the Floppy Controller board has had its ROM switch flipped to off so that the ROM on the Z80 board can take over.

So with this fully loaded set-up, we run CP/M instead of HDOS. And to do that, we use the CP/M Setup disk, to create a CP/M boot disk for this system, along with the Distribution Disk #1 to load the basic files on our new boot disk.

I love the CP/M process. It knows about the H19, and really paints the screen well. It also discovers (and asks) what's part of the system so that the boot disk can be crafted to make later booting easy.

IMPORTANT - in this video (again) the screen on the H19 appears to have a "wave" of brightness on it. That is an artifact of the video itself. The display on the H19 is very solid with none of that wave. I've tried to adjust the camera settings to have a slow-enough shutter speed to eliminate it, and I've gotten close...but not there yet.

At the end of the video, I load-up the Space Pirates disk, and let it start to run. I know, I know, I forgot my CP/M for just a moment and tried to run pirates.com...quickly realizing I should just type in pirates.

After shooting this video, while re-boxing everything, I figured I'd try my home-brew 64K memory board that I had assembled on the H8-7 Breadboard. It worked great.

With that board in place I tried a couple more disks with the following outcome:

• Zen-Calc - ran great
• CP/M Accounting System - CP/M reported bad sector