10-BIT ANALOG TO DIGITAL CONVERTER (ADC)
10.11 10-BIT ANALOG TO DIGITAL CONVERTER (ADC)
10.11.1 Main Characteristics
â– 10-bit Resolution
â– Monotonicity: Guaranteed
â– No missing codes: Guaranteed
â– 3-bit INTCLK/2 Frequency Prescaler
â– Internal/External Trigger availability
â– Continuous/Single Modes
â– Autoscan Mode
â– Power Down Mode
â– 16 10-bit data registers (two per channel)
â– Two analog watchdogs selectable on adjacent
channels
10.11.2 Introduction
The Analog to Digital Converter (ADC) consists of
an input multiplex channel selector feeding a suc-
cessive approximation converter.
Figure 155. ADC Block Diagram
The conversion time depends on the INTCLK fre-
quency and the prescaler factor stored in the
PR[2:0] bits of the CLR2 register (R253-page 63)).
AVDD and AVSS are the high and low level refer-
ence voltage pins. Up to 16 multiplexed Analog In-
puts are available depending on the specific de-
vice type. With the AUTOSCAN feature, a group of
signals can be converted sequentially by simply
programming the starting address of the first ana-
log channel to be converted.
There are two Analog Watchdogs used for the
continuous hardware monitoring of two consecu-
tive input channels selectable by means of the
CC[3:0] bits in the CLR1 register (R252-page 63).
An Interrupt request is generated whenever the
converted value of either of these two analog in-
puts exceeds the upper or lower programmed
threshold values.
INTERRUPT UNIT
INT. VECTOR POINTER
INT. CONTROL REGISTER
INTERNAL
TRIGGER
(from MFT0)
EXTERNAL
TRIGGER
(EXTRG)
CONTROL
LOGIC
COMPARE LOGIC
COMPARE RESULT REGISTER
THRESHOLD H/L REGISTER BU
THRESHOLD H/L REGISTER BL
THRESHOLD H/L REGISTER AH
THRESHOLD H/L REGISTER AL
DATA REGISTER H/L15
DATA REGISTER H/L14
DATA REGISTER H/L13
DATA REGISTER H/L12
DATA REGISTER H/L11
DATA REGISTER H/L10
DATA REGISTER H/L 9
DATA REGISTER H/L 8
DATA REGISTER H/L 7
DATA REGISTER H/L 6
DATA REGISTER H/L 5
DATA REGISTER H/L 4
DATA REGISTER H/L 3
DATA REGISTER H/L 2
DATA REGISTER H/L 1
DATA REGISTER H/L 0
CONVERSION
RESULT
SUCCESSIVE
APPROXIMATION
10
bit
ANALOG TO DIGITAL
CONVERTER
ANALOG
MUX
CKAD
AIN 15
AIN 14
AIN 13
AIN 12
AIN 11
AIN 10
AIN 9
AIN 8
AIN 7
AIN 6
AIN 5
AIN 4
AIN 3
AIN 2
AIN 1
AIN 0
CONTROL REG.2
(CLR2)
CONTROL REG.1
(CLR1)
CK PRESCALER
AUTOSCAN LOGIC
DIVIDER by 2
INTCLK
ANALOG
SECTION
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