Z16M1720ASG1868 Zilog, Z16M1720ASG1868 Datasheet - Page 209

• Manufacturer Part Number: Z16M1720ASG1868
• Description: IC PCMCIA INTERFACE 100-VQFP
• Manufacturer: Zilog

Specifications of Z16M1720ASG1868

• Applications: *
• Interface: *
• Voltage - Supply: *
• Package / Case: 100-LQFP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

UM008101-0601
Selecting An Operating Mode
PIO Port A allows operation in four modes: Mode 0 (output mode), Mode 1
(input mode), Mode 2 (bidirectional mode), and Mode 3 (control mode).
The mode numbers are assigned for mnemonic significance: 0 = Out,
1 = In, 2 = Bidirectional. Port B cannot operate in Mode 2.
The mode of operation must be established by writing a control word to the
PIO in the following format:
Listed in Table 1, Bits D7 and D6 form the binary code that designate mode
of operation:
Table 1. PIO Mode Selection
D7
0
0
1
1
Bits D5 and D4 are ignored. Bits D3-D0 must be set to 1111 to indicate
Set Mode.
Selecting Mode 0 enables any data written to the port output register by
the CPU to be enabled onto the port data bus. The output register contents
may be changed by writing a new data word to the port. Also, the current
contents of the output register may be read back to the Z80 CPU by
executing an input instruction.
When Mode 0 is active, a data write from the CPU causes the port’s
Ready handshake line to go High, thereby notifying the peripheral that
Mode Word
D7
M1
M0
D6
D5
X
D4
X
Signifies Mode Word to be Set
D6
0
1
0
1
D3
1
D2
1
D1
1
D0
1
Mode
0 (output)
1 (input)
2 (bidirectional)
3 (control)
<   % 2 7 2 G T K R J G T C N U
Parallel Input/Output
7 U G T / C P W C N