hmp8190 Intersil Corporation, hmp8190 Datasheet - Page 5

• Manufacturer Part Number: hmp8190
• Description: Ntsc/pal Video Encoder
• Manufacturer: Intersil Corporation

Video Timing Control
The pixel input data and the output video timing of the
HMP8190/HMP8191 are at 50 or 59.94 fields per second
interlaced. The timing is controlled by the BLANK, HSYNC,
VSYNC, FIELD, and CLK2 pins.
HSYNC, VSYNC, and Field Timing
The leading edge of HSYNC indicates the beginning of a
horizontal sync interval. If HSYNC is an output, it is asserted
for about 4.7 s. If HSYNC is an input, it must be active for at
least two CLK2 periods. The width of the analog horizontal
sync tip is determined from the video standard and does not
depend on the width of HSYNC.
The leading edge of VSYNC indicates the beginning of a
vertical sync interval. If VSYNC is an output, it is asserted for
3 scan lines in (MM) NTSC and (M, N) PAL modes or 2.5
scan lines in (B, D, G, H, I, NC) PAL modes. If VSYNC is an
input, it must be asserted for at least two CLK2 periods.
When HSYNC and VSYNC are configured as outputs, their
leading edges will occur simultaneously at the start of an
odd field. At the start of an even field, the leading edge of
VSYNC occurs in the middle of the line.
When HSYNC and VSYNC are configured as inputs, the
HMP8190/HMP8191 provides a programmable HSYNC
window for determining FIELD. The window is specified with
respect to the leading or trailing edge of VSYNC. The edge
is selected in the field control register. When HSYNC is
found inside the window, then the encoder sets FIELD to the
value specified in the field control register.
Preamble Word 1
Preamble Word 2
Preamble Word 3
Status Word
NOTE:
F: 0 = Field 1; 1 = Field 2
V: 0 = Active Line; 1 = Vertical Blanking
H: 0 = Start Active Video; 1 = End Active Video
P3 - P0: Protection bits; Ignored
(OUTPUT)
BLANK
P8-P15
CLK2
Cb 2
PIXEL INPUT
Y 2
5
Cr 2
Y 3
TABLE 3. BT.656 EAV AND SAV SEQUENCES
FIGURE 3. PIXEL INPUT TIMING - BT.656
Cb 4
P15
1
0
0
1
HMP8190, HMP8191
Y 4
P14
F
1
0
0
P13
The HMP8190/HMP8191 provides programmable timing for
the VSYNC input. At the active edge of VSYNC, the encoder
resets its vertical half-line counter to the value specified by
the field control register. This allows the input and output
syncs to be offset, although the data must still be aligned.
The FIELD signal is always an output and changes state
near each leading edge of VSYNC. The delay between the
syncs and FIELD depends on the encoder’s operating mode
as summarized in Table 4. In modes in which the encoder
uses CLK to gate its inputs and outputs, the FIELD signal
may be delayed 0-12 additional CLK2 periods.
Figure 4 illustrates the HSYNC, VSYNC, and FIELD general
timing for (M) NTSC and (M, N) PAL. Figure 5 illustrates the
general timing for (B, D, G, H, I, NC) PAL. In the figures, all
the signals are shown active low (their reset state), and
FIELD is low during odd fields.
V
1
0
0
DIRECTION
“FF”
SYNC I/O
Output
OPERATING MODE
Input
Input
"00"
P12
H
1
0
0
DIRECTION
TABLE 4. FIELD OUTPUT TIMING
BLANK I/O
Don’t Care
Output
Input
“00”
P11
P3
1
0
0
EAV
DELAY
CLK2
148
138
32
P10
P2
1
0
0
“10”
FIELD lags VSYNC switch-
ing from odd to even.
FIELD lags the earlier of
VSYNC and HSYNC when
syncs are aligned when
switching from even to odd.
FIELD lags VSYNC.
FIELD leads VSYNC.
“80”
COMMENTS
P9
P1
1
0
0
“10”
P8
P0
1
0
0