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4) Put the data for the next address in switches 7 through 0, then depress
DEPOSIT NEXT.
5) Repeat step 4 until all bytes have been entered.
6) Raise and release RESET to force all address lights back to zero.
7) Verify the data shown on lights D7 through D0 matches the data byte for
the current address. If the value is correct, go to step 9, otherwise
go to step 8.
8) Put the correct value in switches 7 through 0, then raise DEPOSIT.
9) Depress EXAMINE NEXT
10) Repeat steps 7 through 9 to validate entry of the entire program.
Once the bootstrap loader is entered and verified, we’re almost ready to load
the BASIC paper tape. But first, we must set the run address to zero and then
set the front panel sense switches to tell the checksum loader and BASIC the
type of serial port that is in use:
1) Set all address switches to zero.
2) Raise EXAMINE to set all address lights (and the 8080 program counter)
to zero.
3) Raise A11 and A10 to the up position. This tells the checksum loader
and BASIC that you are using a 2SIO serial board with one stop bit to
load BASIC and to use as your console.
Now we’re finally ready to actually load BASIC!
1) Depress RUN to run the bootstrap loader. If the loader was entered cor-
rectly, address lights A12, and A4-A0 should be on.
2) Transmit the paper tape image by using the “File->Send File” menu op-
tion in TeraTerm. Browse to and select the file “4K Basic Ver 3-2.tap”
which is located in the “Paper Tape and Cassette” folder inside the
“BASIC” folder. Be sure the “binary” checkbox at the bottom of the send
file dialog is checked when sending a paper tape file.
3) Loading BASIC will only take about five seconds at 9600 baud (instead
of seven minutes at 110 baud!). Once loaded, BASIC initializes and
prompts the user for memory size. The prompt may look a bit garbled as
shown:
MEMORY SIZã?
This occurs because 4K BASIC uses bit 7 to store additional informa-
tion. However, because teletypes ignored bit 7, this did not cause a
problem. We can duplicate this effect in TeraTerm by choosing “Setup-
>Serial Port” and setting the “Data” field to 7 bits, and setting the
“Parity” field to “Space.” (Note: These settings must be returned to
8N1 if you need to start over and send the paper tape file once again).
4) Turn on “Caps Lock” on the keyboard.
5) In response to the “MEMORY SIZE” prompt, key in 20000 and press return.
(You can simply press RETURN and let BASIC determine memory size as
long as you have a PROM installed. Otherwise, BASIC will loop forever
and clobber itself while it looks for the end of RAM!).
6) In response to the “TERMINAL WIDTH” prompt, press RETURN.
7) In response to the “WANT SIN?” prompt, key in “Y” and press return.
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