Motorola MC68HC05T16 Technical Data Manual page 88

status bit to be cleared is indeed one before writing a zero, and do not write a 0 to a status bit
which is not 1. Otherwise, status bits which are becoming ones will be inadvertently cleared.
VFINTE - VFLBK interrupt enable
1 (set)
0 (clear) –
MUTE1, MUTE0 - Video mute enable
VFLB - VFLBK status
1 (set)
0 (clear) –
RiCF - Row i display status
1 (set)
9
0 (clear) –
Whenever a row display has been terminated, the corresponding RiCF flag will be set along with
update of CDRC3-CDRC0 field.
MOTOROLA
9-18
– Vertical flyback interrupt enabled.
Vertical flyback interrupt disabled.
MUTE1 MUTE0
0 0
0 1
1 0
1 1
– Vertical flyback (leading edge) signal detected.
No Vertical flyback signal detected.
– Row i display has been terminated.
Row i display has been not terminated.
ON-SCREEN DISPLAY
Function
No video mute
Mute with black color
Mute with G color
Mute with B color
TPG
MC68HC05T16