XR16C872 Datasheet, PDF (43/60 Pages) Exar Corporation – DUAL UART WITH 1284 PARALLEL PORT AND PLUG-AND-PLAY CONTROLLER

DISCONTINUED
XR16C872
“EPP MODE” SIGNAL DESCRIPTIONS
Signal
name
Signal
Type
EPP mode
Name
STROBE#
O
Write#
AUTOFD#
O
DataStb#
SELCTIN#
O
AddrStb#
INIT#
ACK#
BUSY
O
Reset#
I
Intr#
I
Wait#
PE
SELECT
ERR#
PD0-PD7
I
User defined
I
User defined
I
User defined
O
AD0-AD7
Description
Active low. Indicates a write operation, high for a read cycle
Active low. Indicates a Data-Read or Data-Write operation is in
process.
Active low. Indicates an Address-Read or Address-Write opera
tion is in process.
Active low. Peripheral reset.
Peripheral interrupt. Used to generate an interrupt to the host.
Handshake signal. When low it indicates that is okay to start a cycle,
when high it indicates that it is okay to end the cycle.
Not used.
Not used.
Not used.
Bi-directional address / data lines.
EPP Mode Data Transfer Cycle
1. Program executes an I/O write cycle to EPP Data Port-4.
2. The Write# line is asserted and the data is output to the parallel port.
3. The DataStb# is asserted, since Write# is asserted low.
4. The port waits for the acknowledge from the peripheral, Write# deasserted.
5. The DataStr# is deasserted and EPP cycle ends.
6. Write# is asserted low to indicate that the next cycle may begin.
Rev. 1.00
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