W65C22S Datasheet, PDF (12/46 Pages) List of Unclassifed Manufacturers – Versatile Interface Adapter (VIA)

The Western Design Center, Inc.
W65C22S Data Sheet
1.4.Write Handshake Control.
The Write Handshake operation is similar to Read Handshaking. For Write Handshaking, however, the W65C22S
generates the Data Ready signal and the peripheral device must generate the Data Taken return signal. Note that
Write Handshaking may occur on both PA and PB. For a Write Handshake, CA2 or CB2 serve as the Data Ready
output and can operate in either the Handshake Mode or the Pulse Mode. The Data Taken signal is received the
CA1 or CB1. The Data Taken signal sets a flag in the Interrupt Flag Register and clears the Data Ready output
signal, see Figure 1-2.
Note that the selection of Read or Write Handshake operating modes for CA1, CA2, CB1 and CB2 is accomplished
by the Peripheral Control Register (PCR). See Table 1-5.
PHI2
WRITE ORA, ORB
OPERATION
“DATA READY”
HANDSHAKE MODE
(CA2, CB2)
“DATA READY”
PULSE MODE
(CA1.CB1)
“DATA TAKEN”
(CA1,CB1)
IRQB OUPUT
Figure 1-2 Write Handshake (PA and PB)
Table 1-5 CA1, CA2, CB1, CB2 Control1 ($0C)
7
6
5
4
3
2
1
0
PCR
CB2 Control
CB1
Control
CA2 Control
CA1
Control
The Western Design Center
W65C22S
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