Figure 15–10. sequence-of-channels mode example, 3 repeat-single-channel mode – Texas Instruments MSP430x1xx User Manual

Page 306

Conversion Modes

15-16

Figure 15–10. Sequence-of-Channels Mode Example

0140h

0142h

015Ch

015Eh

12–bit S A R

ADC12MEM0

ADC12MEM14

ADC12MEM15

16 x 12–bit

ADC Memory

ADC12MCTL0

ADC12MCTL14

ADC12MCTL15

140h + 2 x CStartAdd

80h + CStartAdd

ADC12MCTL2

ADC12MEM1

0
0
0
0

0144h

0146h

0148h

014Ah

0158h

015Ah

ADC12MEM12

ADC12MEM13

Conversion result 1

0154h

0156h

0150h

0152h

ADC12MEM2

ADC12MEM3

ADC12MEM4

ADC12MEM5

ADC12MCTL12

ADC12MCTL13

0 0 0 1 1

0 0 0 0 0

1 0 1 1 1

1 0 1 0 1

0 0 0 0 0

ADC12MCTL1

ADC12MCTL5

ADC12MCTL4

ADC12MCTL3

014Ch

014Eh

Sequence

080h

081h

08Eh

08Fh

082h

083h

084h

085h

08Ch

08Dh

08Ah

08Bh

088h

089h

086h

087h

select

Multiplexer

E
O

Conversion result 1

VR+/VR–

15.5.3 Repeat-Single-Channel Mode

The repeat-single-channel mode is identical to the single-channel mode, ex-
cept that conversions are repeated on the chosen channel until stopped by
software. Each time a conversion is completed, the results are loaded into the
appropriate ADC12MEMx register and the corresponding interrupt flag
ADC12IFG.x is set to indicate completion of the conversion. Additionally, If the
appropriate interrupt-enable flags are set, an interrupt request is generated
(see the

ADC12 Interrupt Vector Register ADC12IV section).

The conversion mode may be changed without first stopping the conversions.
When this is done, the new mode takes effect after the current conversion
completes (see also the

Switching Between Conversion Modes section).

There are three ways to stop repeated conversions on a single channel:

1) Select single-channel mode instead of repeat-single-channel mode with

the CONSEQ bits. When this is done, the current conversion is completed
normally, the result is loaded into ADC12MEMx, and the associated
interrupt flag ADC12IFG.x is set.

2) Reset the ENC bit (ADC12CTL0.1) to stop conversions after the current

conversion is completed. Again, the result is loaded into ADC12MEMx
and the associated interrupt flag ADC12IFG.x is set.

3) Select single-channel mode instead of repeat-single-channel mode and

then reset the enable-conversion bit (ENC). When this is done, the current
conversion stops immediately. However, the data in memory register
ADC12MEMx is unpredictable and the associated interrupt flag
ADC12IFG.x may or may not be set. This method is generally not
recommended.