19 12-BIT A/D CONVERTER (ADC12A)
S1C31D50/D51 TECHNICAL MANUAL
Seiko Epson Corporation
19-1
(Rev. 2.00)
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.
• Can issue a DMA transfer request when a conversion has completed.
Figure 19.1.1 shows the ADC12A configuration.
Table 19.1.1 ADC12A Configuration of S1C31D50/D51
Item
48-pin package
64-pin package
80-pin package 100-pin package
Number of channels
1 channel (Ch.0)
Number of analog signal inputs per channel
Ch.0: 5inputs
(ADIN00–04)
Ch.0: 7 inputs
(ADIN00–06)
Ch.0: 8 inputs
(ADIN00–07)
Ch.0: 8 inputs
(ADIN00–07)
16-bit timer used as conversion clock and
trigger sources
Ch.0
←
16-bit timer Ch.7
VREFA pin (reference voltage input)
External input
ADC12A Ch.n
Trigger
select circuit
Successive
approximation
control circuit
CNVTRG[1:0]
CNVMD
MODEN
ADST
STMD
AD0D[15:0]
ADSTAT[2:0]
BSYSTAT
SMPCLK[2:0]
VRANGE[1:0]
#ADTRGn
ADINn0
ADINn1
ADINnm
VREFAn
Interrupt
control
circuit
AD0CIF
AD1CIF
ADmCIF
OVIF
AD0CIE
AD1CIE
ADmCIE
OVIE
CPU core
DMA
controller
DMA request
control circuit
ADCDMAENx
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.