HD66712 Datasheet, PDF (44/88 Pages) Hitachi Semiconductor – Dot-Matrix Liquid Crystal Display Controller/Driver

HD66712U
Cursor or Display Shift
Cursor or display shift shifts the cursor position or display to the right or left without writing or reading
display data (Table 10). This function is used to correct or search the display. In a 2-line display, the
cursor moves to the second line when it passes the 40th digit of the first line. In a 4-line display, the
cursor moves to the second line when it passes the 20th character of the line. Note that, all line displays
will shift at the same time. When the displayed data is shifted repeatedly each line moves only
horizontally. The second line display does not shift into the first line position. When this instruction is
executed, extended register enable bit (RE) is reset.
The address counter (AC) contents will not change if the only action performed is a display shift. In low
power mode (LP = 1), whole-display shift cannot be normally performed.
Scroll Enable
When extended register enable bit (RE) is 1, scroll enable bits can be set.
This HSE resister specifies scrolled line with the scroll quantity register. This register consists of 4 bits
for each display line, so a specified line can be shifted by dot unit. When the bit 0 of HSE is 1 in four line
mode (NW = 1), the first line can be shifted, and the bit 1 is specified to shift the second line, the bit 2 is
specified for the third line, and bit 3 is specified for the fourth line. When it shifts the first line in two line
mode (N = 1, NW = 0), both the bit 0 and bit 1 should be set to 1. The bit 2 and bit 3 is specified for the
second line.
In 1 line mode (N = 0, NW = 0), the bit 0 and bit 1 should be specified.
Function Set
Only when the extended register enable bit (RE) is 1, the BE and the LP bits shown below can be
accessed. Bits DL and N can be accessed regardless of RE.
DL: Sets the interface data length. Data is sent or received in 8-bit lengths (DB7 to DB0) when DL is 1,
and in 4-bit lengths (DB7 to DB4) when DL is 0. When 4-bit length is selected, data must be sent or
received twice.
N: When bit NW in the extended function set is 0, a 1- or a 2-line display is set. When N is 0, 1-line
display is selected; when N is 1, 2-line display is selected. When NW is 1, a 4-line display is set. At this
time, N is “Don’t care.”
Note: After changing the N or NW or LP bit, please issue the Return Home or Clear Display instruction
to cancel to shift display.
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