Rev. 1.71
96
April 11, 2017
Rev. 1.71
97
April 11, 2017
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
Analog to Digital Converter
The need to interface to real world analog signals is a common requirement for many electronic
systems. However, to properly process these signals by a microcontroller, they must first be
converted into digital signals by A/D converters. By integrating the A/D conversion electronic
circuitry into the microcontroller, the need for external components is reduced significantly with the
corresponding follow-on benefits of lower costs and reduced component space requirements.
A/D Overview
The devices contain a multi-channel analog to digital converter which can directly interface
to external analog signals, such as that from sensors or other control signals and convert these
signals directly into a 12-bit digital value. The external or internal analog signal to be converted is
determined by the SAINS and SACS bit fields. Note that when the internal analog signal is to be
converted, the pin-shared control bits should also be properly configured except the SAINS and
SACS bit fields. More detailed information about the A/D input signal is described in the “A/D
Converter Control Registers” and “A/D Converter Input Signal” sections respectively.
Part No.
Input Channels
A/D Channel Select Bits
Input Pins
HT66F002
HT66F0025
HT66F003
4
SAINS2~SAINS0,
SACS1~SACS0
AN0~AN3
HT66F004
8
SAINS2~SAINS0,
SACS2~SACS0
AN0~AN7
The accompanying block diagram shows the overall internal structure of the A/D converter, together
with its associated registers.
AN0
AN5
AN6
AN7
12-bit
SAR ADC
ENADC
SADOH[7:0]
SADOL[7:0]
ADBZ
SAINT
SACS[2:0]
V
BG
(1.04V)
VREF
V
RI
Divider
f
SYS
SACKS[2:0]
AV
DD
SAVRS[3:0]
V
R
VREFO
SAINS[2:0]
SAPIN
VREFO
ENOPA
PASR
OPA
MUX
Pin-shared selection
AV
DD
V
R
A/D Converter Structure