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Chapter 24 Analog-to-Digital Converter (ADC12B16C) Block Description
MC9S12XF - Family Reference Manual, Rev.1.19
1084
Freescale Semiconductor
4
MULT
Multi-Channel Sample Mode — When MULT is 0, the ATD sequence controller samples only from the specied
analog input channel for an entire conversion sequence. The analog channel is selected by channel selection
code (control bits CD/CC/CB/CA located in ATDCTL5). When MULT is 1, the ATD sequence controller samples
across channels. The number of channels sampled is determined by the sequence length value (S8C, S4C, S2C,
S1C). The rst analog channel examined is determined by channel selection code (CD, CC, CB, CA control bits);
subsequent channels sampled in the sequence are determined by incrementing the channel selection code or
wrapping around to AN0 (channel 0).
0 Sample only one channel
1 Sample across several channels
3–0
CD, CC,
CB, CA
Analog Input Channel Select Code — These bits select the analog input channel(s) whose signals are
sampled and converted to digital codes.
Table 24-15 lists the coding used to select the various analog input
channels.
In the case of single channel conversions (MULT=0), this selection code species the channel to be examined.
In the case of multiple channel conversions (MULT=1), this selection code species the rst channel to be
examined in the conversion sequence. Subsequent channels are determined by incrementing the channel
selection code or wrapping around to AN0 (after converting the channel dened by the Wrap Around Channel
Select Bits WRAP3-0 in ATDCTL0). In case of starting with a channel number higher than the one dened by
WRAP3-0 the rst wrap around will be AN15 to AN0.
Table 24-15. Analog Input Channel Select Coding
SC
CD
CC
CB
CA
Analog Input
Channel
00000
AN0
0001
AN1
0010
AN2
0011
AN3
0100
AN4
0101
AN5
0110
AN6
0111
AN7
1000
AN8
1001
AN9
1
0
1
0
AN10
1
0
1
AN11
1
0
AN12
1
0
1
AN13
1
0
AN14
1
AN15
Table 24-14. ATDCTL5 Field Descriptions (continued)
Field
Description