THS12082_09 Datasheet, PDF (12/42 Pages) Texas Instruments – 12-BIT, 8 MSPS, SIMULTANEOUS SAMPLING ANALOG-TO-DIGITAL CONVERTERS

THS12082
12-BIT, 8 MSPS, SIMULTANEOUS SAMPLING ANALOG-TO-DIGITAL CONVERTERS
SLAS271B – MAY 2000 – REVISED DECEMBER 2002
FIFO description
In order to facilitate an efficient connection to today’s processors, the THS12082 is supplied with a FIFO. This
integrated FIFO enables a problem-free processing of data. The FIFO is provided as a flexible circular buffer.
The circular buffer integrated in the THS12082 can store up to 16 conversion values. Therefore, the number
of interrupts to be served by a processor can be reduced significantly.
16
1
15
2
14
Read Pointer
3
13
4
12
11
5
Trigger Pointer
6
10
7
98
Write Pointer
Figure 4. Circular Buffer
Data in FIFO
Free
The converted data of the THS12082 is automatically written into the FIFO. To control the writing and reading
process, a write pointer, a read pointer, and a trigger pointer are used. The read pointer always shows the
location which will be read next. The write pointer indicates the location which contains the last written sample.
With a selection of multiple analog input channels, the converted values are written in a predefined sequence
to the circular buffer (autoscan mode). In this way, the channel information for the reading processor is
continually maintained.
The FIFO can be programmed through the control register of the ADC. The user has the ability to select a
specific trigger level from Table 13 in order to choose the configuration which best fits the application. The FIFO
provides the signal DATA_AV, which signals the processor to read the amount of data equal to the trigger level
selected in Table 13. The signal DATA_AV becomes active when the trigger condition is satisfied. The trigger
condition is satisfied when as many values as selected for the trigger level where written into the FIFO.
The signal DATA_AV could be connected to an interrupt input of a processor. In every interrupt service routine
call, the processor must read the amount of data equal to the trigger level from the ADC. The first data represents
the first channel according to the autoscan mode, which is shown in Table 10. The channel information is
therefore always maintained.
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