Z80382 Datasheet, PDF (39/77 Pages) Zilog, Inc. – HIGH-PERFORMANCE DATA COMMUNICATIONS PROCESSORS

Zilog
Z80382/Z8L382
High-Performance Data Communications Processors
HOST INTERFACE
The host interface block in the Z382 includes the 16550 Baud Rate Generator in the Mimic, allowing a wide range
1 ^{Mimic, the Host DMA Mailbox, the ISA PnP Interface and of data rates to be emulated. Two additional 8-bit timers}
the PCMCIA Interface.
are available for programming the FIFO timeout feature
(Four Character-Time Emulation) for both the Receiver
16550 Mimic
and the Transmitter FIFOs.
The Z382 includes a 16x50 Mimic interface that allows it to
emulate the operation of a PC UART. The interface allows
the Z382 to be connected directly to an ISA bus or PCM-
CIA bus without any external circuitry. The Mimic contains
the 16x50 register set and the same interrupt structure.
The data path allows parallel transfer of data to and from
the register set by the internal processor of the Z382.
Control of the register set is maintained by six priority en-
coded interrupts to the Z382. When the PC Host reads or
writes to certain Mimic registers, an interrupt to the Z382 is
generated. Each interrupt can be individually masked off
or all interrupts can be disabled by writing a single bit.
Two 8-bit timers are also available to control the data
transfer rate of the Mimic interface. Their input is tied to a
The 16550 Mimic supports the PC Host interrupt structure
by means of the Plug and Play ISA or PCMCIA interface
modules. COM Port decoding is also provided by the same
modules.
A bit in the Z382 System Configuration Register controls
whether the registers of the 16x50 Mimic interface are ac-
cessible in any page of I/O space, as on the Z8018x family,
because only the lowest eight address lines are decoded,
or whether A15-8 must be zero to access the registers.
The Mimic Interface can transfer both Transmit and Re-
ceive data under control of the Z382Õs DMA channels, thus
minimizing processor overhead and maximizing through-
put in high-speed applications.
COM Port Decode from Plug and Play ISA or PCMCIA
4
Host Address
Decode
16550 Mimic
Register Set
8
6
Host IRQ
Host DMA Control
2
Host IRQ
Receive
Timer
Transmit
Timer
Z382
IRQ
Control
Z80380
Control/ _Addr
ConÞguration
Register
8
Internal Data Bus
Host DMA
Mailbox
Figure 23. 16550 Mimic Block Diagram
DS97Z382000
PRELIMINARY
39