Z80182 Datasheet, PDF (9/109 Pages) Zilog, Inc. – ZILOG INTELLIGENT PERIPHERAL CONTROLLER (ZIP™)

Zilog
PRELIMINARY
Z80182/Z8L182
ZILOG INTELLIGENT PERIPHERAL
/W//REQB. Wait/Request (output, open drain when
programmed for the Wait function, driven High or Low
when programmed for a Request function). This pin is
similar in functionality to /W//REQA but is applicable on
channel B. The /W//REQB signal is multiplexed with the
Z180 MPU CKS signal and the 16550 MIMIC interface
/HTxRDY signal on the CKS//W//REQB//HTxRDY pin.
16550 MIMIC INTERFACE SIGNALS
HD7-HD0. Host Data Bus (input/output, tri-state). In Z80182/
Z8L182 mode 1, the host data bus is used to communicate
between the 16550 MIMIC interface and the PC/XT/AT. It
is multiplexed with the PA7-PA0 of parallel Port A when the
Z80182/Z8L182 is in mode 0.
/HRD. Host Read (input, active Low). In Z80182/Z8L182
mode 1, this input is used by the PC/XT/AT to signal the
16550 MIMIC interface that a read operation is taking
place. In Z80182/Z8L182 mode 0, this pin is multiplexed
with the ESCC /DCDB signal on the /DCDB//HRD pin.
/HDDIS. Host Driver Disable (output, active Low). In Z80182/
Z8L182 mode 1, this signal goes Low whenever the
PC/XT/AT is reading data from the 16550 MIMIC interface.
In Z80182/Z8L182 mode 0, this pin is multiplexed with the
ESCC^™ TxDB signal on the TxDB//HDDIS pin.
HA2-HA0. Host Address (input). In Z80182/Z8L182 mode
1, these pins are the address inputs to the 16550 MIMIC
interface. This address determines which register the
PC/XT/AT accesses. HA0 is multiplexed with /TRxCB on
the /TRxCB/HA0 pin; HA1 is multiplexed with RxDB on the
RxDB/HA1 pin; HA2 is multiplexed with /RTxCB on the
/RTxCB/HA2 pin.
/HCS. Host Chip Select (input, active Low). In Z80182/
Z8L182 mode 1, this input is used by the PC/XT/AT to
select the 16550 MIMIC interface for an access. In Z80182/
Z8L182 mode 0, it is multiplexed with the ESCC /SYNCB
signal on the SYNCB//HCS pin.
/HWR. Host Write (Input, active Low). In Z80182/Z8L182
mode 1, this input is used by the PC/XT/AT to signal the
16550 MIMIC interface that a write operation is taking
place. In Z80182/Z8L182 mode 0, this input is multiplexed
with the ESCC /CTSB signal on the /CTSB//HWR pin.
HINTR. Host Interrupt (output, active High). In Z80182/
Z8L182 mode 1, this output is used by the 16550 MIMIC
interface to signal the PC/XT/AT that an interrupt is pending.
In Z80182/Z8L182 mode 0, this pin is multiplexed with the
ESCC (/DTR//REQB) signal and the Z180 MPU TxS signal
on the TxS//DTR//REQB//HINTR pin.
/HTxRDY. Host Transmit Ready (output, active Low). In
Z80182/Z8L182 mode 1, this output is used by the 16550
MIMIC in DMA mode to signal the PC/XT/AT that the
Transmit Holding Register is empty. In Z80182/Z8L182
mode 0, this pin is multiplexed with the ESCC (/W//REQB)
signal and the Z180 MPU CKS signal on the CKS//W//
REQB//HTxRDY pin.
/HRxRDY. Host Receive Ready (output, active Low). In
Z80182/Z8L182 mode 1, this output is used by the 16550
MIMIC interface in DMA mode to signal the PC/XT/AT that
a data byte is ready in the Receive Buffer. In Z80182/
Z8L182 mode 0, this pin is multiplexed with the ESCC
/RTSB signal and the Z180 MPU /TEND1 signal on the
/TEND1/RTSB /HRxRDY pin.
PARALLEL PORTS
PA7-PA0. Parallel Port A (input/output). These lines can be
configured as inputs or outputs on a bit-by-bit basis when
the Z80182/Z8L182 is operated in mode 0. These pins are
multiplexed with the HD7-HD0 when the Z80182/Z8L182 is
in mode 1.
PB7-PB0. Parallel Port B (input/output). These lines can be
configured as inputs or outputs on a bit-by-bit basis when
the Port function is selected in the System Configuration
register. The pins are multiplexed with the following Z180
peripheral functions: /RTS0, /CTS0, /DCD0, TxA0, RxA0,
TxA1, RxA1, (RxS//CTS1).
PC7-PC0. Parallel Port C (input/output). These lines can
be configured as inputs or outputs on a bit-by-bit basis for
bits PC5-PC0. Bits PC7 and PC6 are input only and read
the level of the external /INT2 and /INT1 pins. When /INT2
and/or /INT1 are in edge capture mode, writing a 1 to the
respective PC7, PC6 bit clears the interrupt capture latch;
writing a 0 has no effect. Bits PC5-PC0 are multiplexed with
the following pins from ESCC channel A: (/W//REQA),
/SYNCA, (/DTR//REQA), /RTSA, /MWR, /CTSA, /DCDA.
The Port function is selected through a bit in the System
Configuration Register.
DS971820600
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