Tandy 1000 SL Technical Reference Manual page 38

A d d r e s s D e s c r i p t i o n
0 0 0 8
DMA C o n t r o l l e r
IOW- = 0 , Write
command R e g i s t e r
B i t
D e s c r i p t i o n
0
0 =
Memory
t o
Memory D i s a b l e
1 =
Memory
t o
Memory E n a b l e
1 0 =
C h a n n e l 0 A d d r e s s Hold D i s a b l e
1 = C h a n n e l 0 A d d r e s s Hold E n a b l e
X
If B i t
0 = 0
2 0 = C o n t r o l l e r E n a b l e
1 =
C o n t r o l l e r D i s a b l e
3
--
0 = N o r m a l
T i m i n g
1 = Compressed T i m i n g
X
If B i t 0 =
1
4 0 = F i x e d P r i o r i t y
1 =
R o t a t i n g P r i o r i t y
5
--
0 = L a t e
W r i t e
S e l e c t i o n
1 = E x t e n d e d W r i t e S e l e c t i o n
X If B i t
3 = 1
6
* - O
=
DREQ S e n s e A c t i v e High
1 =
DREQ
S e n s e A c t i v e Low
7 -0
=
DACK S e n s e A c t i v e Low
1 = DACK S e n s e A c t i v e High
IOR- = 0 , Read S t a t u s R e g i s t e r
B i t D e s c r i p t i o n
0
1 = C h a n n e l
1
1 = C h a n n e l
2 1 = C h a n n e l
3 1 = C h a n n e l
4 1 = C h a n n e l
5
1 = C h a n n e l
6
1 = C h a n n e l
7
1 = C h a n n e l
0 H a s R e a c h e d DMATC
1 Has R e a c h e d DMATC
2 Has R e a c h e d DMATC
3 H a s R e a c h e d DMATC
0 R e q u e s t
1 R e q u e s t
2 R e q u e s t
3 Request
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