MC68HC11G5 Datasheet, PDF (115/195 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller

Freescale Semiconductor, Inc.
Table 9-1. Channel Assignments (continued)
CONV8 = 1
Result in register if
CD CC CB CA Channel Signal MULT = 1 MULT = 0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
AN1 (PE0)
AN2 (PE1)
AN3 (PE2)
AN4 (PE3)
ADR1
ADR2
ADR3
ADR4
ADR1 – 8
ADR1 – 8
ADR1 – 8
ADR1 – 8
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
AN5 (PE4)
AN6 (PE5)
AN7 (PE6)
AN8 (PE7)
ADR5
ADR6
ADR7
ADR8
ADR1 – 8
ADR1 – 8
ADR1 – 8
ADR1 – 8
1
0
X
X
reserved
1
1
0
0
Vrh
ADR5 ADR1 – 8
1
1
0
1
Vrl
ADR6 ADR1 – 8
1
1
1
0
Vrh /2
ADR7 ADR1 – 8
1
1
1
1
Test (reserved)
ADR8 ADR1 – 8
9.3 SINGLE CHANNEL OPERATION
Single channel operation is selected by writing a zero to the MULT bit in the A/D control and status
register (ADCTL). This mode has four variations, which can be selected using the CONV8 and
SCAN bits in the ADCTL register. In the first two variations, the CONV8 bit is clear and the single
selected channel is converted four consecutive times. In the second two variations, the CONV8 bit
is set and the single selected channel is converted eight consecutive times. The state of the SCAN
bit determines whether continuous or single scanning is selected. The channel is selected by the
CD – CA bits in the ADCTL register.
9.3.1 4-Conversion, Single Scan
Whichever Port E bit is selected, the first result will be stored in the ADR5 result register and
the fourth result will be stored in the ADR8 register. After the fourth conversion is complete
all conversion activity is halted until a new conversion command is written to the ADCTL
control register.
9.3.2 4-Conversion, Continuous Scan
Conversions continue to be performed on the selected channel with the fifth conversion being stored
in the ADR5 register (overwriting the first conversion result), the sixth conversion overwrites ADR6,
the seventh overwrites ADR7, and so on continuously. Using this variation, the data in any result
register is at most four conversion times old.
ANALOG-TO-DIGITAL CONVERTER
9-3
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