Figure 12-4. Doubling the ADC Sample Rate
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
ADC Sample Clock
GSYNC
ADC 0 PHASE 0x0 (0.0°)
ADC 1 PHASE 0x8 (180.0°)
18
Using the ADCSPC register, ADC0 and ADC1 may provide a number of interesting applications:
■ Coincident sampling of different signals. The sample sequence steps run coincidently in both
converters.
– ADC Module 0, ADCSPC = 0x0, sampling AIN0
– ADC Module 1, ADCSPC = 0x0, sampling AIN1
■ Skewed sampling of the same signal. The sample sequence steps are 1/2 of an ADC clock (500
µs for a 1Ms/s ADC) out of phase with each other. This configuration doubles the conversion
bandwidth of a single input when software combines the results as shown in Figure
12-5 on page 540.
– ADC Module 0, ADCSPC = 0x0, sampling AIN0
– ADC Module 1, ADCSPC = 0x8, sampling AIN0
Figure 12-5. Skewed Sampling
S1
S2
S2
S3
S3
S4
S4
S5
S5
S6
S6
S7
S7
S8
S8
ADC0
ADC1
S1
12.3.3 Hardware Sample Averaging Circuit
Higher precision results can be generated using the hardware averaging circuit, however, the
improved results are at the cost of throughput. Up to 64 samples can be accumulated and averaged
to form a single data entry in the sequencer FIFO. Throughput is decreased proportionally to the
July 24, 2012540
Texas Instruments-Production Data
Analog-to-Digital Converter (ADC)
OBSOLETE: TI has discontinued production of this device.
