MC9S08QG8_09 Datasheet, PDF (128/314 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Analog-to-Digital Converter (S08ADC10V1)
7
R
ADLPC
W
Reset:
0
6
5
ADIV
4
ADLSMP
3
2
MODE
0
0
0
0
0
Figure 9-10. Configuration Register (ADCCFG)
1
0
ADICLK
0
0
Table 9-5. ADCCFG Register Field Descriptions
Field
Description
7
ADLPC
6:5
ADIV
4
ADLSMP
3:2
MODE
1:0
ADICLK
Low Power Configuration — 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.
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.
Long Sample Time Configuration — 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
Conversion Mode Selection — MODE bits are used to select between 10- or 8-bit operation. See Table 9-7.
Input Clock Select — ADICLK bits select the input clock source to generate the internal clock ADCK. See
Table 9-8.
ADIV
00
01
10
11
Table 9-6. Clock Divide Select
Divide Ratio
1
2
4
8
Clock Rate
Input clock
Input clock ÷ 2
Input clock ÷ 4
Input clock ÷ 8
MODE
00
01
10
11
Table 9-7. Conversion Modes
Mode Description
8-bit conversion (N=8)
Reserved
10-bit conversion (N=10)
Reserved
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 5
126
Freescale Semiconductor