ISA Local Resource Bus
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1
Seven-Segment Display Register
This 16-bit register allows data to be sent to the 4-digit hexadecimal
diagnostic display. The register also allows the data to be read back
.
DIG3[3:0] Hexadecimal value of the most significant digit.
DIG2[3:0] Hexadecimal value of the third significant digit.
DIG1[3:0] Hexadecimal value of the second significant digit.
DIG0[3:0] Hexadecimal value of the least significant digit.
Z85230 ESCC and Z8536 CIO Registers and Port Pins
The Z85230 ESCC is used to provide the two sync/async serial ports on
some MTX series models. The PCLK which can be used to derived the
baud rates, is 5 MHz. Refer to the SCC User’s Manual for programming
information on the Z85230 ESCC device.
The Z8536 CIO is used to provide the modem control lines not provided
by the Z85230 ESCC. Refer to the Z8536 Data Sheet, listed in
, for programming information.
Z8536/Z85230 Registers
Accesses to the Z8536 CIO and the Z85230 ESCC are accomplished via
Port Control and Port Data Registers. The PCLK to the Z8536 is 5 MHz.
Also, a Pseudo IACK Register is also defined to retrieve interrupt vectors
from these devices. The Z8536 CIO has higher priority than the Z85230
ESCC in the interrupt daisy chain. The following list the registers
associated with accessing these two devices:
Register
7-Segment Display Register - Offset $08C0
Bit
SD
15
SD
14
SD
13
SD
12
SD
1
1
SD
10
SD
9
SD
8
SD
7
SD
6
SD
5
SD
4
SD
3
SD
2
SD
1
SD
0
Field
DIG3[3:0]
DIG2[3:0]
DIG1[3:0]
DIG0[3:0]
Operation
R/W
Reset
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X