8 Apr
2016
8 Apr
'16
5:33 a.m.
On Thu, Apr 7, 2016 at 9:35 PM, Pontus Pihlgren <pontus at update.uu.se> wrote:
On Thu, Apr 07, 2016 at 04:08:42PM -0700, Charles
Anthony wrote:
That is my understanding as well.
I haven't actually ever seen any of these beasts; I'm just doing on
documentation that I can find, so I am very likely wrong on some points.
There is a 338 programming manual at
https://archive.org/stream/bitsavers_decpdp8gragmgOct66_2439011/DEC-08-G61B…
with
a the display list opcodes.
The VC8E programming is discussed at
http://homepage.cs.uiowa.edu/~jones/pdp8/man/vc8e.html.
The VC8E has about 8 IO commands, and uses 12 bit coordinates.The commands
boil down to set X, set Y and set intensity to 0 or 1.
The 338 uses 13bit coordinates; the display has 10 bit resolution. The 338
has scaling, 8 intensity levels, delta move, character ROM, and a 36 page
programming manual.
There is a description of the VR14/VC8E at
http://www.pdp8.net/vr14/vr14info.shtml.; it describes the VC8e as 50K dots
per second ont the VR14 monitor, and the 338 as 300K DPS, and mentions that
the 338 had a character ROM.
http://www.chdickman.com/pdp8/spacewar/ built his own VC8/I for his PDP-8
and runs the PDP-8 version of space war on it. He lists the IOT
instructions for the VC8/I; they are similar to the 338.
-- Charles
I have some code that does an X-11 emulation of the Atari Tempest vector
graphics display; I'm thinking of wedging it into the simh PDP8 code to
emulate the 338 and PDP-1 displays.
That woyld be fun :) I could perhaps be used for future PDP-12
and LINC emulators as well.
I have read just a little about the 338. I believe it is more or
less a dedicated PDP-8. Can you say how it compares with other
vector displas, such as VC8E?