Port Handshake Specification Registers
VL-486-4 Reference Manual
CIO Chip – 79
Port Handshake Specification Registers
P
ORT
A/B H
ANDSHAKE
S
PECIFICATION
R
EGISTERS
CIOAHS (READ/WRITE) 28H
CIOBHS (READ/WRITE) 29H
D7
D6
D5
D4
D3
D2
D1
D0
HTS1
HTS0
RWS2
RWS1
RWS0
DTS3
DTS2
DTS1
Port handshake mode is not supported. All bits must be remain in their reset state (0).
P
ORT
C
OMMAND AND
S
TATUS
R
EGISTERS
CIOACS (READ/PARTIAL WRITE) 08H
CIOBCS (READ/PARTIAL WRITE) 09H
D7
D6
D5
D4
D3
D2
D1
D0
IUS/ICB2
IE/ICB1
IP/ICB0
ERR
ORE
IRF
PMF
IOE
Each of these registers contain the primary command and status bits for its port. Other than the
data bits themselves, these are the bits most often accessed in normal port operation. A reset
forces ORE to 1 and all other bits to 0. All bits are readable and four are writable.