Texas Instruments MSP430x1xx User Manual

Page 326

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ADC12 Control Registers

15-36

080h...08Fh

ADC12MCTLx

0

7

rw–(0)

rw–(0)

rw–(0)

rw–(0)

rw–(0)

rw–(0)

rw–(0)

rw–(0)

EOS

Sref, source of reference

INCH, input channel a0 to a11

INCH,

bits 0–3

The INCH (input channel) bits select one of eight external, or one of four internal
analog signals for conversion.

0–7:

a0 to a7

8:

Ve

REF+

9:

V

REF–

/Ve

REF–

10:

Temperature diode

11–15: (AV

CC

– AV

SS

) / 2

Note: Selecting channel 10 automatically turns on the on-chip reference

generator for a voltage source for the temperature diode. However, it
does not enable the V

REF+

output or effect the reference selections for

the conversion.

Sref,

bits4–6

The Sref bits select one of six reference voltage combinations used for
conversion. The conversion is done between the selected voltage range V

R+

and V

R–

.

0:

V

R+

= AV

CC

and V

R–

= AV

SS

1:

V

R+

= V

REF+

and V

R–

= AV

SS

2,3:

V

R+

= Ve

REF+

and V

R–

= AV

SS

4:

V

R+

= AV

CC

and V

R–

= V

REF–

/ Ve

REF–

5:

V

R+

= V

REF+

and V

R–

= V

REF–

/ Ve

REF–

6,7:

V

R+

= Ve

REF+

and V

R–

= V

REF–

/ Ve

REF–

EOS,

bit7

The end-of-sequence bit, when set, indicates the last conversion in a sequence
of conversions.

Note: A sequence will roll over from ADC12MEM15/ADC12MCTL15 to

ADC12MEM0/ADC12MCTL0 if the EOS bit in ADC12MCTL15 is not set.

Note:

If none of the EOS bits is set and a sequence-of-channels
(CONSEQ={1,3}) is selected, resetting the ENC bit will not stop the
sequence. To stop the sequence, first select a single-channel mode
(CONSEQ={0,2}) and then reset ENC. See also the ENC bit description.

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