SN8P275X Series
8-bit micro-controller build-in 12-bit ADC
SONiX TECHNOLOGY CO., LTD
Page 135
Version 0.7
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8 CHANNEL ANALOG TO DIGITAL
CONVERTER
11.1 OVERVIEW
This analog to digital converter has 8-input sources with up to 4096-step resolution to transfer analog signal into 12-bits
digital data. The sequence of ADC operation is to select input source (AIN0 ~ AIN7) at first, then set GCHS and ADS
bit to “1” to start conversion. When the conversion is complete, the ADC circuit will set EOC bit to “1” and final value
output in ADB register. This ADC circuit can select between 8-bit and 12-bit resolution operation by programming
ADLEN bit in ADR register.
A/D
CONVERTER
(ADC)
DA
T
A
B
U
S
8/12
AIN0/P4.0
AIN5/P4.5
AIN2/P4.2
AIN3/P4.3
AIN4/P4.4
AIN1/P4.1
AIN6/P4.6
AIN7/P4.7
A/D
CONVERTER
(ADC)
DA
T
A
B
U
S
8/12
DA
T
A
B
U
S
8/12
AIN0/P4.0
AIN0/P4.0
AIN5/P4.5
AIN5/P4.5
AIN2/P4.2
AIN2/P4.2
AIN3/P4.3
AIN3/P4.3
AIN4/P4.4
AIN4/P4.4
AIN1/P4.1
AIN1/P4.1
AIN6/P4.6
AIN6/P4.6
AIN7/P4.7
AIN7/P4.7
Note: For 8-bit resolution the conversion time is 12 steps.
For 12-bit resolution the conversion time is 16 steps
Note: The analog input level must be between the AVREFH and AVREFL.
Note: The AVREFL connects to VSS internally in SN8P2754, SN8P2755 and SN8P2756.
Note: The AVREFH level must be between the AVDD and 2.0V.
Note: The AVREFL level must be between the VSS and AVREFH - 2.0V.
Note: ADC programming notice:
1. Set ADC input pin I/O direction as input mode
2. Disable pull-up resistor of ADC input pin
3. Disable ADC before enter power down (sleep) mode to save power consumption.
4. Set related bit of P4CON register to avoid extra power consumption in power down mode.
5. Delay 100uS after enable ADC (set ADENB = “1”) to wait ADC circuit ready for conversion.
6. Disable ADC (set ADENB = “0”) before enter sleep mode to save power consumption.