19 12-BIT A/D CONVERTER (ADC12A)
S1C17M20/M21/M22/M23/M24/M25
Seiko Epson Corporation
19-1
TECHNICAL MANUAL (Rev. 1.0)
19 12-bit A/D Converter (ADC12A)
19.1 Overview
The ADC12A is a successive approximation type 12-bit A/D converter.
The features of the ADC12A are listed below.
• Conversion method:
Successive approximation type
• Resolution:
12 bits
• Analog input voltage range:
Reference voltage VREFA to V
SS
• Supports two conversion modes: 1. One-time conversion mode
2. Continuous conversion mode
• Supports three conversion triggers: 1. Software trigger
2. 16-bit timer underflow trigger
3. External trigger
• Can convert multiple analog input signals sequentially.
• Can generate conversion completion and overwrite error interrupts.
Figure 19.1.1 shows the ADC12A configuration.
Table 19.1.1 ADC12A Configuration of S1C17M20/M21/M22/M23/M24/M25
Item
S1C17M20/M23
S1C17M21/M24
S1C17M22/M25
24-pin package
32-pin package
Number of channels
1 channel (Ch.0)
Number of analog signal inputs
per channel
Ch.0: 4 inputs
(ADIN00–ADIN03)
Ch.0: 6 inputs
(ADIN00–ADIN05)
Ch.0: 8 inputs
(ADIN00–ADIN07)
16-bit timer used as conversion
clock and trigger sources
Ch.0
←
16-bit timer Ch.3
ADC12A Ch.n
Trigger
select circuit
Successive
approximation
control circuit
CNVTRG[1:0]
CNVMD
MODEN
ADST
STMD
AD0D[15:0]
ADSTAT[2:0]
BSYSTAT
AD1D[15:0]
ADmD[15:0]
SMPCLK[2:0]
VRANGE[1:0]
#ADTRGn
ADINn0
ADINn1
ADINnm
VREFAn
Interrupt
control
circuit
AD0CIF
AD1CIF
ADmCIF
AD0OVIF
AD1OVIF
ADmOVIF
AD0CIE
AD1CIE
ADmCIE
AD0OVIE
AD1OVIE
ADmOVIE
Interrupt
controller
Inter
nal data
bu
s
Timer
16-bit timer
Ch.k
Underflow
Clock
generator
CLK_T16_k
MUX
+
–
Comparator with
sample & hold circuit
D/A
converter
Figure 19.1.1 ADC12A Configuration
Note: In this chapter, n, m, and k refer to an ADC12A channel number, an analog input pin number, and
a 16-bit timer channel number, respectively.