TV Converter Box User Manual

Conversation Between the TLV1562 and the DSP
15
Interfacing the TLV1562 Parallel ADC to the TMS320C54x DSP
7.4 Dual Interrupt Driven Mode
Using techniques similar to those described in the first two modes for
sampling/converting/sending tasks, the dual mode samples two channels at the
same time and sends out the results in series to the data port. The CSTART
pin
is used to start sampling and converting.
Table 9. DSP Algorithm for Dual Interrupt Driven Mode
Wait cycles for the DSP internally (40MHz DSPCLK):
STEPS TIMING, NOTES
APD=0
ADCSYCLK
= 7.5MHz
APD=0
ADCSYCLK
= 10MHz
APD=1
ADCSYCLK
= 10MHz
APD=1
ADCSYCLK
= 10MHz
1. Set CS Deselect ADC
2. Clear CSTART This starts sampling
3. Wait for t
W(CSTARTL)
t
W(CSTARTL)
= 100ns (APD=0)
t
W(CSTARTL)
= 600ns (APD=1)
≥4 ≥4 ≥24 ≥24
4. Set CSTART This starts the conversion
5. Wait until INT goes low Alternative: ignore the INT signal,
wait 210ns+10 ADCSYSCLK and go
to step number 7
≥62 ≥48 ≥62 ≥48
6. Wait the time t
D(INTL-CSL)
t
D(INTL-CSI)
= 10 ns ≥1 ≥1 ≥1 ≥1
7. Clear CS Select the ADC
8. Clear RD Start communication
9. Wait the time t
EN(DATAOUT)
t
EN(DATAOUT)
= 41 ns ≥2 ≥2 ≥2 ≥2
10. Read sample out from the data port;
reset RD
signal
11. Wait t
W(CSH)
t
W(CSH)
= 50 ns ≥2 ≥2 ≥2 ≥2
12. Clear RD- Start communication
13. Wait the time t
EN(DATAOUT)
t
EN(DATAOUT)
= 41 ns ≥2 ≥2 ≥2 ≥2
14. Read sample out from the data port;
reset RD
signal
15. Set CS Deselect ADC
16. Goto step 2 for the next samples