EM78P417N/418N/419N
8-Bit Microprocessor with OTP ROM
Fig. 6-8 Interrupt Input Circuit
6.7 Analog-To-Digital Converter (ADC)
The analog-to-digital circuitry consists of an 8-bit analog multiplexer; three control
registers (AISR/R8, ADCON/R9, & ADOC/RA), three data registers (ADDATA1/RB,
ADDATA1H/RC, & ADDATA1L/RD) and an ADC with 12-bit resolution as shown in the
functional block diagram below. The analog reference voltage (Vref) and the analog
ground are connected via separate input pins.
The ADC module utilizes successive approximation to convert the unknown analog
signal into a digital value. The result is fed to the ADDATA, ADDATA1H and
ADDATA1L. Input channels are selected by the analog input multiplexer via the
ADCON register Bits.
ADC7
ADC6
ADC5
ADC4
Vref
Power-Down
ADC
Start to Convert
( successive approximation )
ADC3
ADC2
ADC1
ADC0
Fsco
4-1
MUX
Internal RC
7
~
0
2
1
0
3
4
3
11 10
9
8
7
6
5
4
3
2
1
0
6
5
ADCON
ADCON
ADCON
DATA BUS
RF
AISR
ADDATA1H
ADDATA1L
Fig. 6-9 Analog-to-Digital Conversion Functional Block Diagram
42 •
Product Specification (V1.0) 06.23.2005
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
