CHAPTER 11 10-BIT A/D CONVERTER (
µµµµ
PD789436 AND 789456 SUBSERIES)
User’s Manual U15075EJ1V0UM00
198
Figure 11-1. Block Diagram of 10-Bit A/D Converter
Sample & hold circuit
Voltage comparator
Successive
approximation
register (SAR)
Controller
3
A/D conversion result
register 0 (ADCR0)
Tap selector
AV
SS
INTAD0
A/D converter mode
register 0 (ADM0)
Analog input channel
specification register 0 (ADS0)
Internal bus
AV
SS
P-ch
AV
DD
ANI4/P64
ANI5/P65
ANI0/P60
ANI1/P61
ANI2/P62
ANI3/P63
Selector
ADCS0 FR02
FR01
FR00
ADS02 ADS01 ADS00
(1)
Successive approximation register (SAR)
The SAR receives the result of comparing an analog input voltage and a voltage at a voltage tap
(comparison voltage), received from the series resistor string, starting from the most significant bit (MSB).
Upon receiving all the bits, down to the least significant bit (LSB), that is, upon the completion of A/D
conversion, the SAR sends its contents to A/D conversion result register 0 (ADCR0).
(2)
A/D conversion result register 0 (ADCR0)
ADCR0 holds the result of A/D conversion. Each time A/D conversion ends, the conversion result in the
successive approximation register is loaded into ADCR0, which is a 10-bit register.
ADCR0 can be read with a 16-bit memory manipulation instruction.
RESET input makes ADCR0 undefined.
Symbol
ADCR0H (FF14H)
0
0
0
0
0
0
ADCR0L (FF14H)
FF14H,
FF15H
Address After reset
0000H
R/W
R
Caution
When the
µµµµ
PD78F9436, a flash memory version of the
µµµµ
PD789425 or
µµµµ
PD789426, is used,
this register can be accessed in 8-bit units. However, only an object file assembled with
the
µµµµ
PD789425 or
µµµµ
PD789426 can be used. The same is also true for the
µµµµ
PD78F9456, a
flash memory version of the
µµµµ
PD789445 or
µµµµ
PD789446: This register can be accessed in
8-bit units, but only an object file assembled with the
µµµµ
PD789445 or
µµµµ
PD789446 can be
used.
Summary of Contents for mPD789425
Page 2: ...2 User s Manual U15075EJ1V0UM00 MEMO ...
Page 6: ...6 User s Manual U15075EJ1V0UM00 MEMO ...
Page 10: ...10 User s Manual U15075EJ1V0UM00 MEMO ...
Page 24: ...24 User s Manual U15075EJ1V0UM00 MEMO ...
Page 36: ...36 User s Manual U15075EJ1V0UM00 MEMO ...
Page 46: ...46 User s Manual U15075EJ1V0UM00 MEMO ...
Page 176: ...User s Manual U15075EJ1V0UM00 176 MEMO ...
Page 196: ...User s Manual U15075EJ1V0UM00 196 MEMO ...
Page 210: ...User s Manual U15075EJ1V0UM00 210 MEMO ...
Page 262: ...262 User s Manual U15075EJ1V0UM00 MEMO ...
Page 278: ...278 User s Manual U15075EJ1V0UM00 MEMO ...
Page 296: ...296 User s Manual U15075EJ1V0UM00 MEMO ...
Page 298: ...User s Manual U15075EJ1V0UM00 298 MEMO ...