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Rev. 1.10
56
March 02, 2020
Rev. 1.10
57
March 02, 2020
BS83A02L/BS83B04L
Ultra-Low Power Touch Key Flash MCU
BS83A02L/BS83B04L
Ultra-Low Power Touch Key Flash MCU
• PAC Register – BS83B04L
Bit
7
6
5
4
3
2
1
0
Name
PAC7
PAC6
PAC5
PAC4
PAC3
PAC2
PAC1
PAC0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
1
1
1
1
1
1
1
1
Bit 7~0
PAC7~PAC0
: PA7~PA0 Pin type selection
0: Output
1: Input
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 A Output Function Selection
register “n”, labeled as PASn, and Input Function Selection register, labeled as IFS, 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 the digital input
pin, such as INT, CTCK, TC etc., which shares the same pin-shared control configuration with its
corresponding general purpose I/O function when setting the relevant pin-shared control bit. To
select this pin function, in addition to the necessary pin-shared control and peripheral functional
setup aforementioned, it 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.
Device
Register
Name
Bit
7
6
5
4
3
2
1
0
BS83A02L
PAS0
PAS07 PAS06
—
—
PAS03 PAS02
—
—
BS83B04L
PAS0
PAS07 PAS06 PAS05 PAS04 PAS03 PAS02 PAS01 PAS00
PAS1
PAS17 PAS16
—
—
PAS13 PAS12 PAS11 PAS10
IFS
—
—
—
—
—
—
IFS1
IFS0
Pin-shared Function Selection Register List