Z86E3016PSG Datasheet, PDF (91/348 Pages) Zilog, Inc. – Z86E3016PSG

Z8 CPU
User Manual
73
Handshake Operations
When used as an I/O port, Port 1 can be placed under handshake control
by programming the Port 3 Mode register bits D4 and D3 both to 1. In this
configuration, handshake control lines are DAV1 (P33) and RDY1 (P34)
when Port 1 is an input port, or RDY1 (P33) and DAV1 (P34) when Port 1
is an output port. See Figures 37 and 39.
Handshake direction is determined by the configuration (input and output)
assigned to Port 1. For example, if Port 1 is an output port then handshake
is defined as output.
R247 P3M
Port 3 Mode Register
(F7, Write-Only)
D4 D3
00 P33 = Input
P34 = Output
01 P33 = Input
P34 = DM
10 P33 = Input
P34 = DM
11 P33 = DAV1/RDY1 P34 = RDY1/DAV1
Figure 37. Handshake Operation
Port 2
Port 2 is a general-purpose port. Figure 29 shows a block diagram of Port
2. Each of its lines can be independently programmed as input or output
via the Port 2 Mode Register (F6h) as seen in Figure 38. A bit set to a 1 in
P2M configures the corresponding bit in Port 2 as an input, while a bit set
to 0 configures an output line.
UM001602-0904
I/O Ports