Motorola MPC823e Reference Manual page 1058

Video Controller
19.5.2 PAL Example
The PAL (Phase Alternation Line) broadcast method defines a virtual screen of 625 lines,
which are 864 pixels long. However, you can only see 576 of these lines. Each horizontal
line contains 720 pixels during the active line period (which is visible to you) with the rest of
the line's pixels presented during digital blanking. Figure 19-7 illustrates how the frame is
divided into six sections that correlate with the behavior of the FIELD and BLANK signals:
• Lines 1-22: Frame 0 blanking
• Lines 23-310: Frame 0 active video for odd lines
• Lines 311-312: Frame 0 for retrace blanking
• Lines 313-335: Frame 1 blanking
• Lines 336-623: Frame 1 active video for even lines
• Lines 624-625: Frame 1 retrace blanking
LINE BLANK FIELD
1 0
22 0
23 0/1
310 0/1
311 0
312 0
313 0
335 0
336 0/1
623 0/1
624 0
625 0
19-24
0
BLANKING
0
0 A B C
ODD FIELD
ACTIVE VIDEO
FRAME BUFFER A
0
0
RETRACE BLANKING
0
1
BLANKING
1
1
A B C
EVEN FIELD
ACTIVE VIDEO
FRAME BUFFER B
1
1
RETRACE BLANKING
1
Figure 19-7. Interlaced PAL Format
MPC823e REFERENCE MANUAL
D E
D E
FIELD 0
FIELD 1
MOTOROLA