mc908jl16 Freescale Semiconductor, Inc, mc908jl16 Datasheet - Page 135

• Manufacturer Part Number: mc908jl16
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

9.8.4 ADC10 Clock Register (ADCLK)
This register selects the clock frequency for the ADC10 and the modes of operation.
ADLPC — ADC10 Low-Power Configuration Bit
ADIV[1:0] — ADC10 Clock Divider Bits
ADICLK — Input Clock Select Bit
MODE[1:0] — 10- or 8-Bit or External-Triggered Mode Selection
Freescale Semiconductor
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.
ADIV1 and ADIV0 select the divide ratio used by the ADC10 to generate the internal clock ADCK.
Table 9-3
If ACLKEN is clear, ADICLK selects either the bus clock or an alternate clock source as the input clock
source to generate the internal clock ADCK. If the alternate clock source is less than the minimum
clock speed, use the internally-generated bus clock as the clock source. As long as the internal clock
ADCK, which is equal to the selected input clock divided by ADIV, is at a frequency (f
the minimum and maximum clock speeds (considering ALPC), correct operation can be guaranteed.
This bit selects between 10- or 8-bit operation. The successive approximation converter generates a
result which is rounded to 8- or 10-bit value based on the mode selection. This rounding process sets
the transfer function to transition at the midpoint between the ideal code voltages, causing a
quantization error of 1/2
Reset returns 8-bit mode.
1 = Low-power configuration: The power is reduced at the expense of maximum clock speed.
0 = High-speed configuration
1 = The internal bus clock is selected as the input clock source
0 = The alternate clock source IS SELECTED
shows the available clock configurations.
Address:
MODE1
Reset:
Read:
Write:
0
0
1
1
ADLPC
$003F
Bit 7
ADIV1
0
MODE0
0
0
1
1
LSB
Figure 9-7. ADC10 Clock Register (ADCLK)
0
1
0
1
.
ADIV1
Table 9-3. ADC10 Clock Divide Ratio
6
0
ADIV0
MC68HC908JL16 Data Sheet, Rev. 1.1
0
1
0
1
8-bit, right-justified, ADCSC write-triggered mode enabled
10-bit, right-justified, ADCSC write-triggered mode enabled
Reserved.
10-bit, right-justified, external triggered mode enabled
Table 9-4. Mode Selection
ADIV0
5
0
Divide Ratio (ADIV)
ADICLK
4
0
1
2
4
8
MODE1
3
0
Mode
MODE0
Input clock ÷ 1
Input clock ÷ 2
Input clock ÷ 4
Input clock ÷ 8
Clock Rate
2
0
ADLSMP
1
0
ACLKEN
Bit 0
0
ADCK
) between
Registers
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