149
CHAPTER 13 A/D CONVERTER
13.1 A/D Converter Functions
The A/D converter is an 8-bit resolution converter that converts analog inputs into digital values. It can control
up to 5 analog input channels (ANI0 to ANI4).
This A/D converter has the following functions:
(1) A/D conversion with 8-bit resolution
One channel of analog input is selected from ANI0 to ANI4, and A/D conversion is repeatedly executed with a
resolution of 8 bits. Each time the conversion has been completed, interrupt request (INTAD) is generated.
(2) Power-fail detection function
This function is to detect a voltage drop in the battery of an automobile. The result of A/D conversion (value of
the ADCR1 register) and the value of PFT register (PFT: power-fail compare threshold value register) are
compared. If the condition for comparison is satisfied, INTAD is generated.
Figure 13-1. A/D Converter Block Diagram
ANI0/P10
ANI1/P11
ANI2/P12
ANI3/P13
ANI4/P14
Selector
Sample & hold circuit
Voltage comparator
Successive
approximation
register (SAR)
Control
circuit
3
A/D conversion result
register (ADCR1)
Tap selector
AV
REF
AV
SS
INTAD
A/D converter mode register
Analog input channel
specification register
Internal bus
ADS12 ADS11 ADS10
ADCS1 FR12 FR11 FR10
Summary of Contents for mPD780973 Series
Page 2: ...2 MEMO ...
Page 66: ...66 MEMO ...
Page 98: ...98 MEMO ...
Page 138: ...138 MEMO ...
Page 164: ...164 MEMO ...
Page 182: ...182 MEMO ...
Page 204: ...204 MEMO ...
Page 244: ...244 MEMO ...
Page 262: ...262 MEMO ...
Page 278: ...278 MEMO ...
Page 290: ...290 MEMO ...