ISA Local Resource Bus
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Z85230 ESCC and Z8536 CIO Registers and Port Pins
The Z85230 ESCC (Enhanced Serial Communication Controller) is used
to provide the two sync/async serial ports on MVME3600/ 4600 series
models. The PCLK (master clock input) which can be used to derive the
baud rates, is 10 MHz. Refer to the SCC User’s Manual for programming
information on the Z85230 ESCC device.
The Z8536 CIO furnishes the modem control lines not provided by the
Z85230 ESCC and supplies a method to inquire the module ID of the two
sync/async serial ports that reside on the MVME761 module. Refer to the
Z8536 Data Sheet 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 table lists the registers
associated with accessing these two devices:
Table 1-20. Z8536/Z85230 Access Registers
PCI I/O Address
Function
0000 0840
Z85230: Port B (Serial Port 4) Control
0000 0841
Z85230: Port B (Serial Port 4) Data
0000 0842
Z85230: Port A (Serial Port 3) Control
0000 0843
Z85230: Port A (Serial Port 3) Data
0000 0844
Z8536 CIO: Port C’s Data Register
0000 0845
Z8536 CIO: Port B’s Data Register
0000 0846
Z8536 CIO: Port A’s Data Register
0000 0847
Z8536 CIO: Control Register
0000 084F
Z85230/Z8536 Pseudo IACK