SN8P2977
8-Bit Micro-Controller with Regulator, PGIA, 24-bit ADC
SONiX TECHNOLOGY CO., LTD
Page 113
Version 1.7
13.6.4
Output Word Rate
Delta-Sigma ADC provides variable output word rate (WR) from 7.6 Hz up to 5.2 kHz, which output word rate is
decided by setting bits of
ADCKS
and
OSR [2:0].
The ADC output code with slow output word rate is more stable than
fast one. In ADC
’s application, that should be tradeoff between ADC’s output word rate and stability (ENOB). The
following table shows the ADC output word rate with setting:
ADC Output Word Rate Table:
13.6.5
ADCM1- ADC Mode1 Register
Bit[7:4]:
IRVS[3:0]: ADC Internal Reference Voltage Selection.
IRVS[3:0]
V
ref
source
IRVS[3:0]
V
ref
source
AVE= 1.5V
AVE= 2.0V
AVDDR= 2.4V
AVDDR= 2.8V
AVDDR= 3.2V
0000
0.225V
0.3V
0100
0.36V
0.42V
0.48V
0001
0.375V
0.5V
0101
0.60V
0.70V
0.80V
0010
0.525V
0.7V
0110
0.84V
0.98V
1.12V
0011
0.750V
1.0V
0111
1.20V
1.40V
1.60V
IRVS[3:0]
V
ref
source
IRVS[3:0]
V
ref
source
VBG=1.2V
External Input
10xx
0.8V
11xx
R+/R-
Note: (1) Vref source from AVE (1.5V/2.0V), AVE pin connect 1uf capacitors to ground.
(2) When CHS=0x66h Vref voltage have to set IRVS[3:0]=10xx.
Bit3
ACHPENB: ADC Chopper Control bit.
(Always set “1”)
0: ADC Chopper Disable.
1: ADC Chopper Enable.
Bit1
ADGN: ADC Gain Selection
0 = ADC Gain x 1
1 = ADC Gain x 2
Bit0:
ADCENB: ADC function control bit
0 = Disable 24-bit ADC,
1 = Enable 24-bit ADC
Note_1: The Operation range of ADC Reference Voltage (Vref) is from 0.36V to 1.2V@AVDDR=2.4V.
Note_2: In Temperature detection mode(CHS=0x66) ,The Operation range of ADC Reference Voltage (Vref)
is from VBG*2/3= 0.8V (IRVS=10xx).
ADCKS
OSR [2:0]
ADC
clock
WR
ADCKS
OSR [2:0]
ADC
clock
WR
0
000
250KHz
3.9 kHz
1
000
333KHz
5.2KHz
0
001
1.95 kHz
1
001
2.6KHz
0
010
976 Hz
1
010
1.3KHz
0
011
244 Hz
1
011
325Hz
0
100
61 Hz
1
100
81Hz
0
101
30.5 Hz
1
101
40Hz
0
110
15.2 Hz
1
110
20Hz
0
111
7.6 Hz
1
111
10Hz
093H
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ADCM1
IRVS3
IRVS2
IRVS1
IRVS0
ACHPENB
-
ADGN
ADCENB
R/W
R/W
R/W
R/W
R/W
R/W
-
R/W
R/W
After Reset
0
1
1
0
1
-
0
0