Pin-Shared Functions - Holtek BS86DH12C Manual

PCNS0: PC0 sink current selection
Bit 0
0: Sink current=Level 0 (Min.)
1: Sink current=Level 1 (Max.)

Pin-shared Functions

The flexibility of the microcontroller range is greatly enhanced by the use of pins that have more
than one function. Limited numbers of pins can force serious design constraints on designers but by
supplying pins with multi-functions, many of these difficulties can be overcome. For these pins, the
desired function of the multi-function I/O pins is selected by a series of registers via the application
program control.
Pin-shared Function Selection Registers
The limited number of supplied pins in a package can impose restrictions on the amount of functions
a certain device can contain. However by allowing the same pins to share several different functions
and providing a means of function selection, a wide range of different functions can be incorporated
into even relatively small package sizes. The device includes Port "x" Output Function Selection
register "n", labeled as PxSn, and Input Function Selection register, labeled as IFSi, which can select
the desired functions of the multi-function pin-shared pins.
The most important point to note is to make sure that the desired pin-shared function is properly
selected and also deselected. For most pin-shared functions, to select the desired pin-shared function,
the pin-shared function should first be correctly selected using the corresponding pin-shared control
register. After that the corresponding peripheral functional setting should be configured and then the
peripheral function can be enabled. However, a special point must be noted for some digital input
pins, such as INT, xTCKn, PTPI, etc, which share the same pin-shared control configuration with
their corresponding general purpose I/O functions when setting the relevant pin-shared control bit
fields. To select these pin functions, in addition to the necessary pin-shared control and peripheral
functional setup aforementioned, they must also be set as an input by setting the corresponding bit
in the I/O port control register. To correctly deselect the pin-shared function, the peripheral function
should first be disabled and then the corresponding pin-shared function control register can be
modified to select other pin-shared functions.
Register
Name
7
PAS0 PAS07
PAS1 PAS17
PBS0 PBS07
PBS1 PBS17
PCS0 PCS07
IFS0 —
IFS1 —
Rev. 1.00
High Voltage Touch A/D Flash MCU with HVIO
Bit
6 5 4
PAS06 PAS05 PAS04
PAS16 PAS15 PAS14
PBS06 PBS05 PBS04
PBS16 PBS15 PBS14
PCS06 PCS05 PCS04
— SDAPS1 SDAPS0
— — —
Pin-shared Function Selection Register List
68
BS86DH12C
3 2 1
PAS03 PAS02 PAS01
PAS13 PAS12 PAS11
PBS03 PBS02 PBS01
PBS13 PBS12 PBS11
PCS03 PCS02 PCS01
SCLPS1 SCLPS0 RXPS1
PTPIPS PTCKPS CTCK1PS CTCK0PS
October 26, 2018
0
PAS00
PAS10
PBS00
PBS10
PCS00
RXPS0