Rev. 1.00
118
September 11, 2018
Rev. 1.00
119
September 11, 2018
HT45F4050
A/D NFC Flash MCU
HT45F4050
A/D NFC Flash MCU
Analog to Digital Converter – ADC
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 Converter Overview
The device contains 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. It also can convert the internal signals, such as the internal
reference voltage, 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 using the SAINS bit field, the external channel analog input will be automatically be
switched off. More detailed information about the A/D converter input signal is described in the "A/D
Converter Control Registers" and "A/D Converter Input Signals" sections respectively.
External Input Channels
Internal Analog Signals
A/D Signal Select
13: AN0~AN12
6: AV
DD
, AV
DD
/2, AV
DD
/4, V
R
, V
R
/2, V
R
/4
SAINS3~SAINS0,
SACS3~SACS0
The accompanying block diagram shows the overall internal structure of the A/D converter, together
with its associated registers.
Pin-shared
Selection
SACS3~SACS0
SAINS3~SAINS0
A/D Converter
START
ADBZ
ADCEN
AV
SS
A/D Clock
÷ 2
N
(N=0~7)
f
SYS
SACKS2~
SACKS0
AV
DD
ADCEN
SADOL
SADOH
AN0
AN1
AN12
A/D Converter
Reference Voltage
A/D Data
Registers
ADRFS
PGA
V
RI
V
BGREF
PGAGS1~PGAGS0
(Gain=1/1.667/2.5/3.333)
ADPGAEN
V
R
AV
DD
VREFI
PGAIS
SAVRS1~SAVRS0
VREF
Pin-shared
Selection
Pin-shared
Selection
AV
DD
AV
DD
/2
AV
DD
/4
V
R
V
R
/2
V
R
/4
AV
SS
A/D Converter Structure