Specifications

7.0.5
PROGRAM MEMORY
A cursory memory te$t is performed, usin~ 32-bit
lonsword instructions. The test is in three basic sections:
I. Clear proSram memor~ (wri~e all zeroes). This performs an initial
check on continuity of memor~ addressins.
2. Restart at the be~innins of memory. Read the current lonSword for
all zeroes, write all ones, read for all ones and pro~ress. to the
next lon~word until end of memor~.
3. Restart at the beSinninS of memor~+ Read the c~rrent lon~word for
all ones, write checkerboard pattern +1 ($55555555), read to verify,
write checkerboard pattern +2 ($AAAAAAAA), read to verify, clear the
location (write all zeroes), read for all zeroes and proSress to
the next lonswo~d until end of memory.
7.0.6
VECTOR IKITIALISATION
All 256 exception vectors are initialised to point to
exception-recover~ code. Unimplemented vectors point to a common
exception handler which cleans UP the stack and, when in Maintenance
Mode, Sene rates an error messaSe indicatins which vector occurred and
what the value of the access address and prOSram counter was.
7.0.7
MOTOROLA 6845 CRT CONTROLLER
The onl~ read/write resister of the eRTC is the cursor
re~ister, which we test by writins and immediately verif~ing all data
patterns available; decrementins from SFFFFFF to zero. Upon completion
of the diasnostic, resisters are initialised to define the screen size
as 1088 pixels wide b~ 864 pixels hi~h (sivins a pixel separation of
approximatelY 1/78 inches, or .3256mm); as follows:
RO
Rl
R2
R3
R4
R5
R6
R7
R8
R9
RIO
Rll
R12
R13
R14
R15
(1472/32)-1
1088132
(1088/32)+3
(0*16>+6
(900/12)-1
5
864112
(864/12)+1-1 =
=
4S
= 34
= 37
= 06
= 74
= 05
= 72
72
= 00
= 11
o
12-1
o
o
o
o
o
o
= 00
= 00
= 00
= 00
= 00
= 00
total horizontal characters per line -1
displa~ed horizontal characters per line
horizontal sync position in characters
vertical/horizontal s~nc widths in characters
total vertical character rows per screen -1
adJust~ent to vertical sync to force 60-Hz
displa~ed vertical character rows per screen
vertical s~nc position in character rows +1 -1
non-interlaced mode, no skew
scan lines per character row -1
cursor start
cursor end
start address high bste
start address low byte
cursor high b~te
cursor low byte