4501_M Datasheet, PDF (151/212 Pages) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 4500 SERIES

4501 Group
APPLICATION
2.4 A/D converter
2.4.1 Related registers
(1) A/D control register Q1
A/D operation mode control bit and analog input pin selection bits are assigned to register Q1.
Set the contents of this register through register A with the TQ1A instruction. The TAQ1 instruction
can be used to transfer the contents of register Q1 to register A.
Table 2.4.1 shows the A/D control register Q1.
Table 2.4.1 A/D control register Q1
A/D control register Q1
at reset : 00002 at RAM back-up : state retained R/W
Q13 A/D operation mode control bit
0 A/D conversion mode
1 Comparator mode
Q12 Not used
0
This bit has no function, but read/write is enabled.
1
Q11 Q10
Selected pins
Q11
0 0 AIN0
Analog input pin selection bits ^{0 1 AIN1}
Q10
1 0 Not available
1 1 Not available
Notes 1: “R” represents read enabled, and “W” represents write enabled.
2: When A/D converter is used, Q12 is not used.
2.4.2 A/D converter application examples
(1) A/D conversion mode
Outline: Analog input signal from a sensor can be converted into digital values.
Specifications: Analog voltage values from a sensor is converted into digital values by using a 10-
bit successive comparison method. Use the AIN0 pin for this analog input.
Figure 2.4.2 shows the A/D conversion mode setting example.
Rev.2.01 Feb 07, 2005
REJ09B0192-0201
2-34