Z8F0113HJ005EG Datasheet, PDF (58/245 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F0823 Series
Product Specification
43
Port A–C Data Direction Subregisters
The Port A–C Data Direction Subregister is accessed through the Port A–C Control Regis-
ter by writing 01H to the Port A–C Address Register; see Table 22.
Table 22. Port A–C Data Direction Subregisters (PxDD)
Bit
Field
RESET
R/W
Address
7
DD7
6
DD6
5
DD5
4
DD4
3
DD3
2
DD2
1
DD1
0
DD0
1
1
1
1
1
1
1
1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
If 01H in Port A–C Address Register, accessible through the Port A–C Control Register.
Bit
Description
[7:0]
DDx
Data Direction
These bits control the direction of the associated port pin. Port Alternate Function operation
overrides the Data Direction register setting.
0 = Output. Data in the Port A–C Output Data Register is driven onto the port pin.
1 = Input. The port pin is sampled and the value written into the Port A–C Input Data Register.
The output driver is tristated.
Note: x indicates the specific GPIO port pin number (7–0).
Port A–C Alternate Function Subregisters
The Port A–C Alternate Function Subregister (Table 23) is accessed through the Port A–C
Control Register by writing 02H to the Port A–C Address Register. The Port A–C Alter-
nate Function subregisters enable the alternate function selection on pins. If disabled, pins
functions as GPIO. If enabled, select one of four alternate functions using alternate func-
tion set subregisters 1 and 2 as described in the the Port A–C Alternate Function Set 1
Subregisters section on page 48 and the Port A–C Alternate Function Set 2 Subregisters
section on page 49. See the GPIO Alternate Functions section on page 34 to determine the
alternate function associated with each port pin.
Caution: Do not enable alternate functions for GPIO port pins for which there is no associated al-
ternate function. Failure to follow this guideline can result in unpredictable operation.
PS024315-1011
PRELIMINARY
GPIO Control Register Definitions