ST72734 datasheet(57/144 Pages) STMICROELECTRONICS

57 / 144 page

ST72774/ST727754/ST72734

57/144

SYNC PROCESSOR (SYNC) (Cont’d)

4.4.3 Input Signals

The Sync Processor has the following inputs (TTL

level):

– VSYNCI1 Vertical Sync input1

– HSYNCI1 Horizontal Sync input1 or Composite

sync

– VSYNCI2 Vertical Sync input2

– HSYNCI2 Horizontal Sync input2 or Composite

sync

Note: The above input pairs can be used for DSUB or

BNC connectors. To select these inputs use the

HVSEL bit in the POLR register.

– CSYNCI Sync on Green (external extractor)

Note: If the CSYNCI pin is needed for another I/O func-

tion, the composite sync signal can be connected to

HSYNCI using the SCI0 bit in the MCR register.

– HFBACK Horizontal Flyback input

– VFBACK Vertical Flyback input

4.4.4 Input Signal Waveforms

– The input signals must contain only synchroniza-

tion pulses. In case of serration pulses on CSYN-

CI/HSYNCI, the pulse width should be less than

8µs.

– The VSYNCI signal is internally connected to

Timer Input Capture 1 (ICAP1).

– The HSYNCI or CSYNCI signal, prescaled by

256, is internally connected to Timer Input Cap-

ture 2 (ICAP2).

– Typical timing range: See Figure 38 and 39

– If the timer clock is 2 MHz (external oscillator fre-

quency 24 MHz):

PV accuracy = +/- 1 Timer clock (500ns)

PH*256 accuracy = +/- 1 Timer clock (500ns)

(PV= Vertical pulse, PH = Horizontal pulse)

4.4.5 Output Signals

The Sync Processor has the following outputs:

HSYNCO Horizontal Sync Output

Enable: SYNOP bit in ENR register

Programmable polarity:

HS0/HS1 bits in MCR register

In case of composite sync signal, the signal can be

blanked by software during the vertical period

(HINH bit in ENR register).

In case of separate sync, no blanking is generated.

VSYNCO Vertical Sync Output

Enable: SYNOP bit in ENR register

Programmable polarity:

VOP bit in the MCR register

In case of composite sync the delay of the

extracted Vsync signal is:

minimum: 500ns + HSYNCO pulse width

maximum: 8750ns (max. threshold in ex-

traction mode)

ST72734 数据表(PDF) 57 Page - STMicroelectronics

ST72734 数据表(HTML) 57 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载