K60P100M100SF2RM Datasheet, PDF (802/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

ADC Signal Descriptions
Table 34-1. ADC Signal Descriptions (continued)
Signal
Description
I/O
DADM[3:0]
Differential analog channel inputs
I
AD[23:4]
Single-ended analog channel inputs
I
V_REFSH
Voltage reference select high
I
V_REFSL
Voltage reference select low
I
V_DDA
Analog power supply
I
V_SSA
Analog ground
I
34.2.1 Analog power (V_DDA)
The ADC analog portion uses V_DDA as its power connection. In some packages, V_DDA is
connected internally to V_DD. If externally available, connect the V_DDA pin to the same
voltage potential as V_DD. External filtering may be necessary to ensure clean V_DDA for
good results.
34.2.2 Analog ground (V_SSA)
The ADC analog portion uses V_SSA as its ground connection. In some packages, V_SSA is
connected internally to V_SS. If externally available, connect the V_SSA pin to the same
voltage potential as V_SS.
34.2.3 Voltage reference select
V_REFSH and V_REFSL are the high and low reference voltages for the converter.
The ADC can be configured to accept one of two voltage reference pairs for V_REFSH and
V_REFSL. Each pair contains a positive reference that must be between the minimum Ref
Voltage High and V_DDA, and a ground reference that must be at the same potential as
V_SSA. The two pairs are external (V_REFH and V_REFL) and alternate (V_ALTH and V_ALTL).
These voltage references are selected using the REFSEL bits in the SC2 register. The
alternate (V_ALTH and V_ALTL) voltage reference pair may select additional external pins or
internal sources depending on MCU configuration. Refer to the Chip Configuration
information on the Voltage References specific to this MCU.
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
802
Freescale Semiconductor, Inc.