Color Detection Registers H And L (Cderh, Cderl) - Hitachi HD64411 Q2 User Manual

5 . 5 . 7

Color detection registers H and L (CDERH, CDERL)

Bit: 15 14
CDERH: — —
Initial value: — —
Read/Write: — —
Bit: 15 14
CDERL: CDG CDG
Initial value: * *
Read/Write: R/W R/W
Note: * Value is retained.
Color detection registers H and L (CDERH, CDERL) are 16-bit readable/writable registers. When
the display data output from pins DD17 to DD0 matches the values set in these registers, 1 is
output from the CDE pin. Color detection is performed by means of the CDE pin during the
blanking period. Pins DD0 to DD17 all go low during this period. Therefore, if both CDERH and
CDERL are cleared to 0, CDE pin output will go high during the blanking period. Similarly, if
either CDERH or CDERL is not 0, the CDE pin will go low during the blanking period.
Bits 15 to 8, 1, and 0 of CDERH, and bits 9, 8, 1, and 0 of CDERL are reserved. Only 0 should
be written to these bits.
CDERH/L bits CDR, CDG, and CDB retain their values in a reset.
154
13 12 11 10 9
— — — — —
— — — — —
— — — — —
13 12 11 10 9
CDG CDG CDG CDG —
* * * * —
R/W R/W R/W R/W —
8 7 6 5 4
— CDR CDR CDR CDR
— * * * *
— R/W R/W R/W R/W
8 7 6 5 4
— CDB CDB CDB CDB
— * * * *
— R/W R/W R/W R/W
3 2 1 0
CDR CDR — —
* * — —
R/W R/W — —
3 2 1 0
CDB CDB — —
* * — —
R/W R/W — —