p87c770aar NXP Semiconductors, p87c770aar Datasheet - Page 56

• Manufacturer Part Number: p87c770aar
• Description: Microcontrollers Ntsc With On-screen Display Closed Caption
• Manufacturer: NXP Semiconductors

Philips Semiconductors
18.9.9
A status register is provided that holds information that the processor can use to regulate the way data is written into the
display unit. The register is split into a read only and write only register. Both use the same address.
Table 91 Status Register (address 87F8H); read only
Table 92 Description of SR bits
1999 Jun 11
Microcontrollers for NTSC TVs with On-Screen
Display (OSD) and Closed Caption (CC)
BUSY
BIT
7
7
6
5
4
3
2
1
0
S
TATUS
R
SYMBOL
EGISTER
FIELD
BUSY
SCRL
SCR3
SCR2
SCR1
SCR0
6
(SR)
Character display active or vertical sync. If BUSY = 0, this indicates that the
processor can access the display unit without causing effects on the screen. The lead
time is 4 ms, this is implemented to allow the microcontroller to finish the current access
to the display memory. Two modes are provided to switch between the text horizontal
blank area or vertical blank area.
Random information.
1st or 2nd Field of vertical frame.
Scroll busy. If SCRL = 1, this bit indicates that the scroll function is in progress. When
this bit is set, the automatic scroll function is started. It is automatically cleared on
completion. If forced to a logic 0, the scroll function will be terminated as if all lines were
scrolled. Subsequent logic 0 writes will cause the scroll row to increment by one.
First scroll row select. The value specified by these 4 bits selects the actual row that is
the first one to be displayed in the scroll area. This value is modified by the automatic
scroll function.
FIELD
5
SCRL
4
56
SCR3
3
DESCRIPTION
SCR2
2
P8xCx70 family
SCR1
1
Product specification
SCR0
0