Z8F1680SH020SG Datasheet, PDF (86/412 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F1680 Series
Product Specification
61
7.11.4. Port A–E Alternate Function Subregisters
The Port A–E Alternate Function Subregister, shown in Table 24, is accessed through the
Port A–E Control Register by writing 02H to the Port A–E Address Register. The Port A–
E Alternate Function subregisters enable the alternate function selection on the pins; if dis-
abled, the pins function as GPIO. If enabled, select one of the four alternate functions
using Alternate Function Set Subregisters 1 and 2 as described in the Port A–E Alternate
Function Set 1 Subregisters section on page 64 and the Port A–E Alternate Function Set 2
Subregisters section on page 64. To determine the alternate function associated with each
port pin, see the GPIO Alternate Functions section on page 47.
Caution: Do not enable alternate functions for GPIO port pins for which there is no associated
alternate function. Failure to follow this guideline results in unpredictable operation.
Table 24. Port A–E Alternate Function Subregisters (PxAF)
Bits
Field
Reset
R/W
Address
7
6
5
4
3
2
1
0
AF7
AF6
AF5
AF4
AF3
AF2
AF1
AF0
00H (Ports A–C); 01H (Port D); 00H (Port E);
R/W
If 02H in Port A–D Address Register, accessible through the Port A–E Control Register.
Bit
[7:0]
AF
Description
Port Alternate Function enabled
0 = The port pin is in NORMAL Mode and the DDx bit in the Port A–E Data Direction
subregister determines the direction of the pin.
1 = The alternate function selected through Alternate Function set subregisters are enabled.
Port-pin operation is controlled by the alternate function.
PS025015-1212
PRELIMINARY
General-Purpose Input/Output