MC81F4x16
22. 12-BIT ADC
ADCH
(Select one input pin
of the assigned pins)
Clock
Selector
ADCLK
AN0
AN1
AN2
EOC Flag
M
U
X
Input Pins
+
-
Comparator
Control
Logic
AN13
AN14
BGR
Reference
Voltage
ADDRH (R), ADDRL (R)
Vref AVss
Figure 22-1 A/D Converter Block Diagram
The 12-bit A/D converter (ADC) module uses successive approximation logic to convert analog levels
entering at one of the 16 input channels to equivalent 12-bit digital values. The analog input level
must lie between the V
and V values. The A/D converter has the analog comparator with
REF
SS
successive approximation logic, D/A converter logic (resistor string type), A/D mode register (ADMR),
16 multiplexed analog data input pins (AD0-AD14,BGR), and 12-bit A/D conversion data output
register (ADDRH/ADDRL).
142
October 19, 2009 Ver.1.35