TLC2554, TLC2558

5-V, 12-BIT, 400 KSPS, 4/8 CHANNEL, LOW POWER,

SERIAL ANALOG-TO-DIGITAL CONVERTERS WITH AUTO POWER DOWN

SLAS220A –JUNE 1999

9

POST OFFICE BOX 655303

TLC2554/TLC2558 conversion modes (continued)

repeat sweep mode (mode 11)

Repeat sweep mode (mode 11) works the same way as mode 10 except the operation has an option to continue

even if the FIFO threshold is reached. Once the FIFO has reached its programmed threshold, an interrupt (INT)

is generated. Then two things may happen:

1.

The host may choose to act on it (read the FIFO) or ignore it. If the next cycle is a read FIFO cycle, all of

the data stored in the FIFO is retained until it has been read in order.

2.

If the next cycle is not a read FIFO cycle, or another CSTART is generated, all of the content stored in the

FIFO is cleared before the next conversion result is stored in the FIFO, and the sweep is continued.

Table 3. TLC2554/TLC2558 Conversion Mode

CONVERSION

MODE

CFR

D(6,5)

SAMPLING

TYPE

OPERATION

One shot

00

Normal

•

Single conversion from a selected channel

•

CS or FS to start select/sampling/conversion/read

•

One INT or EOC generated after each conversion

•

Host must serve INT by selecting channel, and converting and reading the previous output.

Extended

•

Single conversion from a selected channel

•

CS to select/read

•

CSTART to start sampling and conversion

•

One INT or EOC generated after each conversion

•

Host must serve INT by selecting next channel and reading the previous output.

Repeat

01

Normal

•

Repeated conversions from a selected channel

•

CS or FS to start sampling/conversion

•

One INT generated after FIFO is filled up to the threshold

•

Host must serve INT by either 1) (FIFO read) reading out all of the FIFO contents up to the

threshold, then repeat conversions from the same selected channel or 2) writing another

command(s) to change the conversion mode. If the FIFO is not read when INT is served, it

is cleared.

Extended

•

Same as normal sampling except CSTART starts each sampling and conversion when CS is

high.

Sweep

10

Normal

•

One conversion per channel from a sequence of channels

•

CS or FS to start sampling/conversion

•

One INT generated after FIFO is filled up to the threshold

•

Host must serve INT by (FIFO read) reading out all of the FIFO contents up to the threshold,

then write another command(s) to change the conversion mode.

Extended

•

Same as normal sampling except CSTART starts each sampling and conversion when CS is

high.

Repeat sweep

11

Normal

•

Repeated conversions from a sequence of channels

•

CS or FS to start sampling/conversion

•

One INT generated after FIFO is filled up to the threshold

•

Host must serve INT by either 1) (FIFO read) reading out all of the FIFO contents up to the

threshold, then repeat conversions from the same selected channel or 2) writing another

command(s) to change the conversion mode. If the FIFO is not read when INT is served it is

cleared.

Extended

•

Same as normal sampling except CSTART starts each sampling and conversion when CS is

high.

NOTE: Programming the EOC/INT pin as the EOC signal works for mode 00 only. The other three modes automatically generate an INT signal

irrespective of whether EOC/INT is programmed.