HT45R35V

Rev. 1.00

21

January 15, 2009

Analog Switch

There are 12 analog switch lines in the device for RC1~RC12, and three corresponding Analog Switch Control regis-

ters, which are ASCR0, ASCR1 and ASCR2.

If the configuration options select PA0~PA3 to be normal I/O pins, then the corresponding bit 0~bit3 bits in the ASCR0

register will be unimplemented and will be read as zero.

Bit No.

Label

Function

0

AS1ON

Defines RC1 analog switch is on or off. AS1ON=

0=Analog switch 1 on, and RC1 is disconnected to pull-low

1=Analog switch 1 off, and RC1 is connected to pull-low or not according ASPLON0 register

1

AS2ON

Defines RC2 analog switch is on or off. AS2ON=

0=Analog switch 2 on, and RC2 is disconnected to pull-low

1=Analog switch 2 off, and RC2 is connected to pull-low or not according ASPLON0 register

2

AS3ON

Defines RC3 analog switch is on or off. AS3ON=

0=Analog switch 3 on, and RC3 is disconnected to pull-low

1=Analog switch 3 off, and RC3 is connected to pull-low or not according ASPLON1 register

3

AS4ON

Defines RC4 analog switch is on or off. AS4ON=

0=Analog switch 4 on, and RC4 is disconnected to pull-low

1=Analog switch 4 off, and RC4 is connected to pull-low or not according ASPLON1 register

4

AS5ON

Defines RC5 analog switch is on or off. AS5ON=

0=Analog switch 5 on, and RC5 is disconnected to pull-low

1=Analog switch 5 off, and RC5 is connected to pull-low or not according ASPLON2 register

5

AS6ON

Defines RC6 analog switch is on or off. AS6ON=

0=Analog switch 6 on, and RC6 is disconnected to pull-low

1=Analog switch 6 off, and RC6 is connected to pull-low or not according ASPLON2 register

6

AS7ON

Defines RC7 analog switch is on or off. AS7ON=

0=Analog switch 7 on, and RC7 is disconnected to pull-low

1=Analog switch 7 off, and RC7 is connected to pull-low or not according ASPLON3 register

7

AS8ON

Defines RC8 analog switch is on or off. AS8ON=

0=Analog switch 8 on, and RC8 is disconnected to pull-low

1=Analog switch 8 off, and RC8 is connected to pull-low or not according ASPLON3 register

ASCR0 (1AH) Register

If the configuration options select PA4~PA7 to be normal I/O pins, then the corresponding bit 0~bit3 bits in the ASCR1

register will be unimplemented and will be read as zero.

Bit No.

Label

Function

0

AS9ON

Defines RC9 analog switch is on or off. AS9ON=

0=Analog switch 9 on, and RC9 is disconnected to pull-low

1=Analog switch 9 off, and RC9 is connected to pull-low or not according ASPLON4 register

1

AS10ON

Defines RC10 analog switch is on or off. AS10ON=

0=Analog switch 10 on, and RC10 is disconnected to pull-low

1=Analog switch 10 off, and RC10 is connected to pull-low or not according ASPLON4 register

2

AS11ON

Defines RC11 analog switch is on or off. AS11ON=

0=Analog switch 11 on, and RC11 is disconnected to pull-low

1=Analog switch 11 off, and RC11 is connected to pull-low or not according ASPLON5 register

3

AS12ON

Defines RC12 analog switch is on or off. AS12ON=

0=Analog switch 12 on, and RC12 is disconnected to pull-low

1=Analog switch 12 off, and RC12 is connected to pull-low or not according ASPLON5 register

4~7

¾

Unused bit, read as

²0²

ASCR1 (1BH) Register