NEC uPD72257, Preliminary User'S Manual

Page: 186 / 343

6.10.2.14 VInSCANLINEINT - Scanline interrupt control register
This register holds the unscaled scanline number at which a Video Input scanline
interrupt VInSCLINT is generated.
It can be selected for which field the interrupt is asserted (first field, second field
or both).
Access
This register can be read/written in 32-bit units.
Address <VIn_Base> + 28
H
Initial Value
0000 0000
H
. This register is initialized by any reset.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
R R R R R R R R R R R R R R R R
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0
FLD2
EN
FLD1
EN
SLINT[11:0]
R R R/W R/W R/W
Writing to the read-only bits is ignored, reading returns undefined values.
Bit Bit name Function
13 FLD2EN
Enable scanline interrupt for second field
0 scanline interrupt for second field disabled
1 scanline interrupt for second field enabled
12 FLD1EN
Enable scanline interrupt for first field
0 scanline interrupt for first field disabled
1 scanline interrupt for first field enabled
11 to 0 SLINT[11:0] Number of the unscaled scanline to generate the interrupt
The scanline interrupt VInSCLINT is activated under following conditions:
• First field scanline interrupt
-
if VInACTSCANLINE.ACTSL[11:0] = VInSCANLINEINT.SLINT
[11:0] > 0 and
- VInSCANLINEINT.FLD1EN = 1 or VInSCANLINEINT.FLD2EN =
1 and
- VInACTSCANLINE.AFLD = 0
• Second field scanline interrupt
-
if VInACTSCANLINE.ACTSL[11:0] = VInSCANLINEINT.SLINT
[11:0] > 0 and
- VInSCANLINEINT.FLD1EN = 1 or VInSCANLINEINT.FLD2EN =
1 and
- VInACTSCANLINE.AFLD = 1
If VInSCANLINEINT.SLINT[11:0] = 0, no scanline interrupt is generated.
In case of interlaced video capturing one VOnSCLINT is generated per field (if any
for both fields is enabled by VInSCANLINEINT.FLD1EN = 1 or
VInSCANLINEINT.FLD2EN = 1), thus two interrupts per frame.
Chapter 6 Video Input (Ravin-M only)
186
Preliminary User's Manual S19203EE1V3UM00