Epson Geneva / PX8 info
Brian Donaldson
Are there still any Epson Geneva or PX8 users out there? (btw is there and
difference between the two?) I acquired one a while back, and have now got
the thing back up and running. This required replacing the nicads in the
computer and RAM pack, and the figuring out of the DIP switch settings,
which seem to have gotten scrambled at some stage.
The original software in ROM was CPM 2.2, Wordstar, and MS Basic. Now
while I can happily live with Wordstar, MS Basic was not my kind of
programming language, so a plan had to be made....
Having found the promform software on the CPM site, I thought my problems
were solved, however this was not to be. Anyway, I wound up writing my own
ROM disk image generating software, and now have my favorite assembler /
linker on the Epson.
btw: My present system for writing new Epson software is as follows:-
compile, assemble, and link on a DOS box using a CPM emulator; generate a
ROM disk image using my makerom software; then download to the Epson with
an Eprom emulator. Once the code is right, its then a simple matter to burn
the Eprom. (all this takes less time than it does to compile under MS C++
<g>)
Anyway, I have a few queries which perhaps someone can answer:
1) MS Basic writes to the screen in graphics mode, and I would love to be
able to do this in C, so I need some info regarding the system memory & I/O
mapping. (I have gone so far as to peek the entire 64K area, whilst
setting and clearing a pixel, to see if I can find a byte which changes,
but with no luck so far.)
2) Does anyone have the pinout for the 50 pin expansion connector, or any
other info which might be useful? (I plan to interface an ADC / DAC, and
perhaps some bank switched memory)
If there is any interest in the ROM image software, I will gladly upload
it, or generate a ROM file for anyone needing it.
Bye for now,
-
Roger Ivie
In article <01bd9c4d$2f372580$LocalHost@default>, Brian Donaldson wrote:
>If there is any interest in the ROM image software, I will gladly upload
>it, or generate a ROM file for anyone needing it.
Why not set up a web page somewhere from which people can download it.
That's what I did with mine (see http://cc.usu.edu/~ivie/pxfs.html)...
I have an ANSI boatload (as opposed to an ISO boatload) of documentation
about the PX-8, but I haven't seen it since I moved a couple of years
ago. I suspect it'll be a couple more years before I stumble across it.
--
Roger Ivie
Design Analysis Associates
75 West 100 South
Logan, UT 84321
mailto:ri...@daa-utah.com
phoneto:(435)753-2212
Will Rose
Brian Donaldson (bdo...@mweb.co.za) wrote:
: Are there still any Epson Geneva or PX8 users out there? (btw is there and
: difference between the two?) I acquired one a while back, and have now got
: the thing back up and running. This required replacing the nicads in the
: computer and RAM pack, and the figuring out of the DIP switch settings,
: which seem to have gotten scrambled at some stage.
: The original software in ROM was CPM 2.2, Wordstar, and MS Basic. Now
: while I can happily live with Wordstar, MS Basic was not my kind of
: programming language, so a plan had to be made....
: Having found the promform software on the CPM site, I thought my problems
: were solved, however this was not to be. Anyway, I wound up writing my own
: ROM disk image generating software, and now have my favorite assembler /
: linker on the Epson.
: btw: My present system for writing new Epson software is as follows:-
: compile, assemble, and link on a DOS box using a CPM emulator; generate a
: ROM disk image using my makerom software; then download to the Epson with
: an Eprom emulator. Once the code is right, its then a simple matter to burn
: the Eprom. (all this takes less time than it does to compile under MS C++
: <g>)
: Anyway, I have a few queries which perhaps someone can answer:
: 1) MS Basic writes to the screen in graphics mode, and I would love to be
: able to do this in C, so I need some info regarding the system memory & I/O
: mapping. (I have gone so far as to peek the entire 64K area, whilst
: setting and clearing a pixel, to see if I can find a byte which changes,
: but with no luck so far.)
You have to feed graphics data to the screen processor:
PSET, entry point WBOOT+30H
PSET is the entry point for the subroutine which replaces graphic screen
data at a specified address in accordance with a specified logical
operation. The graphics screen is sequential in memory, with each dot
corresponding to one bit. The screen memory starts at 8380H has a
length of F00H bytes. Each byte thus corresponds to eight dots across
the screen. Since there are 480 dots, the second row of the screen
starts at byte 83BCH. Logical operation is needed if single bytes
need to be set.
Entry parameters:
B Data
C 1-and 2-or 3-xor others-nop
HL Graphics screen address
Return parameters:
A 00H-normal FFH-character screen mode other-address not in VRAM.
: 2) Does anyone have the pinout for the 50 pin expansion connector, or any
: other info which might be useful? (I plan to interface an ADC / DAC, and
: perhaps some bank switched memory)
Name Number Description
AB15 7 Z-80 address no buffer output only
14 3
13 4
12 1
11 2
10 13
9 16
8 15
7 14
6 11
5 12 Z-80 address no buffer
4 9
3 10
2 6
1 5
0 8
BB7 24 Z-80 data no buffer
6 23
5 22
4 21
3 20
2 19
1 18
0 17
/WAIT 28
/BURQ 25
/BUAK 26
/MRQ 36
/RD 35
/WR 37
/IORQ 40
/MI 27
/CLK 38
/RS 33 System reset
/INTEX 43 External interrupt
SPI 34 External speaker input
/BK2 48 Bank 2 switching signal
DW 42 RF control for expansion DRAM
DCAS 41 RF control for expansion DRAM
OFF 44 Logic power supply ON signal
TXD 46 82c51 TXD output signal
/RXD 45 RXD signal to 82c51
VB1 47 Battery PSU.
/HLTA 30 Batter PSU, switch controlled.
VCH 39 Battery charging supply.
VL 29 Logic power supply.
GND 31,32 Signal ground.
CG 49,50 Chassis ground.
: If there is any interest in the ROM image software, I will gladly upload
: it, or generate a ROM file for anyone needing it.
Note that the ROM layout varies with different sizes of ROMs