Datasheet

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22.2.7.3 Continuous Transfer
A continuous transfer is selected if ADC10CT bit is set. The DTC does not stop after block one (in one-
block mode) or block two (in two-block mode) has been transferred. The internal address pointer and
transfer counter are set equal to ADC10SA and n respectively. Transfers continue starting in block one. If
the ADC10CT bit is reset, DTC transfers cease after the current completion of transfers into block one (in
one-block mode) or block two (in two-block mode) have been transferred.
22.2.7.4 DTC Transfer Cycle Time
For each ADC10MEM transfer, the DTC requires one or two MCLK clock cycles to synchronize, one for
the actual transfer (while the CPU is halted), and one cycle of wait time. Because the DTC uses MCLK,
the DTC cycle time is dependent on the MSP430 operating mode and clock system setup.
If the MCLK source is active but the CPU is off, the DTC uses the MCLK source for each transfer, without
re-enabling the CPU. If the MCLK source is off, the DTC temporarily restarts MCLK, sourced with
DCOCLK, only during a transfer. The CPU remains off, and MCLK is again turned off after the DTC
transfer. The maximum DTC cycle time for all operating modes is show in Table 22-2.
Table 22-2. Maximum DTC Cycle Time
CPU Operating Mode Clock Source Maximum DTC Cycle Time
Active mode MCLK = DCOCLK 3 MCLK cycles
Active mode MCLK = LFXT1CLK 3 MCLK cycles
Low-power mode LPM0/1 MCLK = DCOCLK 4 MCLK cycles
Low-power mode LPM3/4 MCLK = DCOCLK 4 MCLK cycles + 2 µs
(1)
Low-power mode LPM0/1 MCLK = LFXT1CLK 4 MCLK cycles
Low-power mode LPM3 MCLK = LFXT1CLK 4 MCLK cycles
Low-power mode LPM4 MCLK = LFXT1CLK 4 MCLK cycles + 2 µs
(1)
(1)
The additional 2 µs are needed to start the DCOCLK. See the device-specific data sheet for
parameters.
22.2.8 Using the Integrated Temperature Sensor
To use the on-chip temperature sensor, select the analog input channel INCHx = 1010. Any other
configuration is done as if an external channel was selected, including reference selection, conversion-
memory selection, etc.
The typical temperature sensor transfer function is shown in Figure 22-13. When using the temperature
sensor, the sample period must be greater than 30 µs. The temperature sensor offset error is large.
Deriving absolute temperature values in the application requires calibration. See the device-specific data
sheet for the parameters. See Section 24.2.2.1 for the calibration equations.
Selecting the temperature sensor automatically turns on the on-chip reference generator as a voltage
source for the temperature sensor. However, it does not enable the V
REF+
output or affect the reference
selections for the conversion. The reference choices for converting the temperature sensor are the same
as with any other channel.
549
SLAU144J–December 2004–Revised July 2013 ADC10
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