Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
31-27
Preliminary
Table 31-19. ADC0_CR Field Descriptions
Field
Description
ADC0_
EN
ADC0 Enable. Enables ADC0 to perform A/D conversions. Refer to
Section 31.4.5.1, “Enabling and Disabling the
,” for details.
0 ADC is disabled. Clock supply to ADC0 is stopped.
1 ADC is enabled and ready to perform A/D conversions.
Note: The bias generator circuit inside the ADC ceases functioning when this bit is negated.
Note: Conversion commands sent to a disabled ADC are ignored by the ADC control hardware.
Note: When the ADC0_EN status is changed from asserted to negated, the ADC clock will not stop until it
reaches its low phase.
bits 1–3
Reserved.
ADC0_
EMUX
ADC0 External Multiplexer Enable. When ADC0_EMUX is asserted, the MA pins will output digital values
according to the number of the external channel being converted for selecting external multiplexer inputs. Refer
to
Section 31.4.6, “Internal/External Multiplexing
,” for a detailed description about how ADC0_EMUX affects
channel number decoding.
0 External multiplexer disabled; no external multiplexer channels can be selected.
1 External multiplexer enabled; external multiplexer channels can be selected.
Note: The ADC0_EMUX bit must only be written when the ADC0_EN bit is negated. ADC0_EMUX can be set
during the same write cycle used to set ADC0_EN.
5–10
Reserved.
ADC0_
CLK_PS
ADC0 Clock Prescaler. The ADC0_CLK_PS field controls the system clock divide factor for the ADC0 clock as
in
Section 31.4.5.2, “ADC Clock and Conversion Speed
,” for details about how to set
ADC0_CLK_PS.
The ADC0_CLK_PS field must only be written when the ADC0_EN bit is negated. This field can be configured
during the same write cycle used to set ADC0_EN.
Table 31-20. System Clock Divide Factor for ADC Clock
ADC0_CLK_PS
System Clock
Divide Factor
0b00000
2
0b00001
4
0b00010
6
0b00011
8
0b00100
10
0b00101
12
0b00110
14
0b00111
16
0b01000
18
0b01001
20
0b01010
22
0b01011
24
0b01100
26