Z8F6421PM020SC Datasheet, PDF (77/299 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers Z8 Encore-R 64K Series

Z8 Encore!^® 64K Series
Product Specification
57
Port A-H Data Direction Sub-Registers
The Port A–H Data Direction sub-register is accessed through the Port A–H Control regis-
ter by writing 01H to the Port A–H Address register (Table 16).
Table 16. Port A-H Data Direction Sub-Registers
BITS
7
6
5
4
3
2
1
0
FIELD ^DD7
DD6
DD5
DD4
DD3
DD2
DD1
DD0
RESET
1
R/W
R/W
ADDR
If 01H in Port A-H Address Register, accessible through Port A-H Control Register
DD[7:0]—Data Direction
These bits control the direction of the associated port pin. Port Alternate Function opera-
tion overrides the Data Direction register setting.
0 = Output. Data in the Port A–H Output Data register is driven onto the port pin.
1 = Input. The port pin is sampled and the value written into the Port A-H Input Data Reg-
ister. The output driver is tri-stated.
Port A–H Alternate Function Sub-Registers
The Port A–H Alternate Function sub-register (Table 17) is accessed through the Port A–
H Control register by writing 02H to the Port A–H Address register. The Port A–H Alter-
nate Function sub-registers select the alternate functions for the selected pins. Refer to the
GPIO Alternate Functions section to determine the alternate function associated with
each port pin.
Caution:
Do not enable alternate function for GPIO port pins which do not have an
associated alternate function. Failure to follow this guideline may result in
unpredictable operation.
Table 17. Port A-H Alternate Function Sub-Registers
BITS
7
6
5
4
3
2
1
0
FIELD ^AF7
AF6
AF5
AF4
AF3
AF2
AF1
AF0
RESET
0
R/W
ADDR
R/W
If 02H in Port A-H Address Register, accessible through Port A-H Control Register
PS019915-1005
General-Purpose I/O