Datasheet

Chapter 9 Analog-to-Digital Converter (S08ADC10V1)
MC9S08SH8 MCU Series Data Sheet, Rev. 3
132 Freescale Semiconductor
7654 3 210
R
ADLPC ADIV ADLSMP MODE ADICLK
W
Reset: 0 0 0 0 0 0 0 0
Figure 9-10. Configuration Register (ADCCFG
Table 9-5. ADCCFG Register Field Descriptions
Field Description
7
ADLPC
Low Power Configuratio — ADLPC controls the speed and power configuration of the successive
approximation converter. This is used to optimize power consumption when higher sample rates are not required.
0 High speed configuration
1 Low power configuration: {FC31}The power is reduced at the expense of maximum clock speed.
6:5
ADIV
Clock Divide Select — ADIV select the divide ratio used by the ADC to generate the internal clock ADCK.
Table 9-6 shows the available clock configurations.
4
ADLSMP
Long Sample Time Configuratio — ADLSMP selects between long and short sample time. This adjusts the
sample period to allow higher impedance inputs to be accurately sampled or to maximize conversion speed for
lower impedance inputs. Longer sample times can also be used to lower overall power consumption when
continuous conversions are enabled if high conversion rates are not required.
0 Short sample time
1 Long sample time
3:2
MODE
Conversion Mode Selection — MODE bits are used to select between 10- or 8-bit operation. See Table 9-7.
1:0
ADICLK
Input Clock Select — ADICLK bits select the input clock source to generate the internal clock ADCK. See
Table 9-8.
Table 9-6. Clock Divide Select
ADIV Divide Ratio Clock Rate
00 1 Input clock
01 2 Input clock ÷ 2
10 4 Input clock ÷ 4
11 8 Input clock ÷ 8
Table 9-7. Conversion Modes
MODE Mode Description
00 8-bit conversion (N=8)
01 Reserved
10 10-bit conversion (N=10)
11 Reserved