SN32F280 Series
32-Bit Cortex-M0 Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 93
Version 1.1
Note:
1. For 8-bit resolution the conversion time is 12 steps. For 12-bit resolution the conversion time is 16
steps
2. ADC_PCLK shall be less than 16MHz.
3. The analog input level must be between the AVREFH and AVREFL.
4. The AVREFH level must be between the AVDD and 2.0V.
5. ADC programming notice
Disable ADC
(set ADENB = “0”) before enter low-power (Sleep/Deep-sleep) mode to save
power consumption.
Delay 100us after enable ADC (set ADENB = “1”) to wait ADC circuit ready for conversion.
7.2 ADC CONVERTING TIME
The ADC converting time is from ADS=1 (Start to ADC convert) to EOC=1 (End of ADC convert). The converting time
duration is depend on ADC resolution and ADC clock rate.
ADC clock source is controlled by ADCKS[2:0] bits. The ADC converting time affects ADC performance. If input high
rate analog signal, it is necessary to select a high ADC converting rate. If the ADC converting time is slower than analog
signal variation rate, the ADC result would be error. So to select a correct ADC clock rate and ADC resolution to decide
a right ADC converting rate is very important.
12-bit ADC conversion time = 1/(ADC clock /4)*16 sec
ADLEN
ADCKS
[2:0]
ADC Clock
ADC_PCLK = 4 MHz
ADC_PCLK = 12 MHz
ADC_PCLK = 16 MHz
ADC
Conversion
Time (us)
ADC
Conversion
Rate (KHz)
ADC
Conversion
Time (us)
ADC
Conversion
Rate (KHz)
ADC
Conversion
Time (us)
ADC
Conversion
Rate (KHz)
1
000
ADC_PCLK
16
62.5
5.33
187.5
4
250
001
ADC_PCLK/2
32
31.25
10.67
93.75
8
125
010
ADC_PCLK/4
64
15.625
21.33
46.875
16
62.5
011
ADC_PCLK/8
128
7.813
42.67
23.437
32
31.25
100
ADC_PCLK/16
256
3.906
85.3
11.718
64
15.625
101
ADC_PCLK/32
512
1.953
170.67
5.859
128
7.813
8-bit ADC conversion time = 1/(ADC clock /4)*12 sec
ADLEN
ADCKS
[2:0]
ADC Clock
ADC_PCLK = 4 MHz
ADC_PCLK = 12 MHz
ADC_PCLK = 16 MHz
ADC
Conversion
Time (us)
ADC
Conversion
Rate (KHz)
ADC
Conversion
Time (us)
ADC
Conversion
Rate (KHz)
ADC
Conversion
Time (us)
ADC
Conversion
Rate (KHz)
0
000
ADC_PCLK
12
83.333
4
250
3
333.333
001
ADC_PCLK/2
24
41.667
8
125
6
166.667
010
ADC_PCLK/4
48
20.83
16
62.5
12
83.333
011
ADC_PCLK/8
96
10.416
32
31.25
24
41.667
100
ADC_PCLK/16
192
5.208
64
15.625
48
20.83
101
ADC_PCLK/32
384
2.604
128
7.813
96
10.416
Содержание SN32F280 Series
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