D6467 datasheet(22/68 Pages) NEC

22 / 68 page

µPD6467

Data Sheet S14455EJ1V0DS00

3. DETAILS OF COMMANDS

3.1 Video RAM Batch Clear Command

This command can be used to clear the video RAM with a single command (regardless of whether the MSB or LSB

comes first)

(MSB)

(LSB)

00000000

The following contents are set by the video RAM batch clear command.

•

Clears all the character data (Display Off Data (FEH)) of the video RAM (12 rows, 28 columns). No data blinks.

•

Video RAM write address: (Row 0, column 0)

•

Standard size for all rows as character size (SV1, SV0, SH1, SH0) = (0, 0, 0, 0)

•

All rows specified for output pin selection (OD1, OD0) = (0, 0)

•

Display OFF, LC oscillation ON, blinking OFF

The time required for clearing the video RAM can be calculated by the following expression. Do not input any

command during this time.

t (Time required for video RAM clearing) = Video RAM clear time

= 10 (

µs) + 12/fOSC (MHz) × 336

= 10 (

µs) + 24/fOSC2 (MHz) × 336

fOSC (MHz): LC oscillation frequency or external input clock frequency (when

×1 frequency mode

is selected)

fOSC2 (MHz): External input clock frequency (when

×2 frequency mode is selected)

To clear the video RAM, the dot clock (OSCIN pin) must be input. Be sure to input the clock when the input of an

external clock is selected.

Remark

This command resets the hardware of the IC by inputting a signal to the PCL pin. While initializing the

IC including clearing the video RAM and the test mode, the video RAM batch clear command executes

software reset to initialize the IC, and does not clear the test mode.

D6467 Datasheet(PDF) 22 Page - NEC