Texas Instruments TLV1562 manual Mono Interrupt Driven Mode Using CSTART, SLAA040

Conversation Between the TLV1562 and the DSP

7.3Mono Interrupt Driven Mode Using CSTART

Use the CSTART signal when two or more ADCs must sample/convert signals at the same time. Instead of the RD signal, the timing for sampling and converting is started with the edges of the CSTART signal. The RD signal is still required to get the data out of the ADC and onto the bus.

Table 8. DSP Algorithm for Mono Interrupt Driven Mode Using CSTART

Wait cycles for the DSP internally (40MHz DSPCLK):

STEPS

TIMING, NOTES

APD=0

APD=0

APD=1

APD=1

ADCSYCLK

ADCSYCLK

ADCSYCLK

ADCSYCLK

= 7.5 MHz

= 10 MHz

= 10 MHz

= 10 MHz

1.

Set

Deselect ADC

CS

2.

Clear

tTis starts sampling

CSTART

3.

Wait for tW(CSTARTL)

tW(CSTARTL) = 100 ns (APD=0)

≥

4

≥

4

≥ 24

≥ 24

tW(CSTARTL) = 600 ns (APD=1)

4.

Set

This starts the conversion

CSTART

5.

Wait until

goes low

Alternative: ignore the

signal,

≥ 33

≥ 21

≥ 33

≥ 21

INT

INT

wait 14ns+5 ADCSYSCLK and goto

step number 7

6.

Wait the time tD(INTL-CSI)

tD(INTL-CSI) = 10 ns

≥

1

≥

1

≥

1

≥

1

7.

Clear

Select the ADC

CS

8.

Clear

Start communication

RD

9.

Wait the time tEN(DATAOUT)

tEN(DATAOUT) = 41 ns

≥

2

≥

2

≥

2

≥

2

10.

Read sample out from the data port;

Reset

signal

RD

11.

Set

Deselect ADC

CS

12.Go to step 2 for the next samples

14SLAA040