PCF2119AU/2DA/2 NXP [NXP Semiconductors], PCF2119AU/2DA/2 Datasheet - Page 29

• Manufacturer Part Number: PCF2119AU/2DA/2
• Description: LCD controllers/drivers
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
PCF2119X_5
Product data sheet
10.2.2.1 Clear_display
10.2.2.2 Return_home
10.2.2 Standard instructions (bit H = 0)
The previous Set_CGRAM or Set_DDRAM command determines if data is written into
CGRAM or DDRAM. After writing, the address counter automatically increments or
decrements by 1, in accordance with the Entry_mode_set (see
4 to bit 0 of CGRAM data are valid, bit 7 to bit 5 are ‘don’t care’.
Table 16.
Clear_display: writes usually the character code 20h (blank pattern) into all DDRAM
addresses except for the character sets ‘R’ and ‘V’ where the character code 20h is not a
blank pattern.
In addition Clear_display
The instruction Clear_display requires extra execution time. This may be allowed by
checking the busy flag bit BF or by waiting until the 165 clock cycles have elapsed. The
latter must be applied where no read-back options are foreseen, as in some
Chip-On-Glass (COG) applications.
Remark: When using the character sets ‘R’ or ‘V’, where the character code 20h is not the
blank pattern, the following alternative instruction set has to be used:
Table 17.
Return_home: Sets the DDRAM address counter to logic 0 and switches a shifted
display back to an unshifted state. The DDRAM content remain unchanged. The cursor or
blink position goes to the left of the first display line. Bit I_D and bit S of the
Entry_mode_set instruction remain unchanged.
Bit
RS
R/W
7 to 0
Bit
RS
R/W
7 to 0
1. Switch display off (Display_ctl, bit D = 0).
2. Write a blank pattern into all DDRAM addresses (Write_data).
3. Switch display on (Display_ctl, bit D = 1).
•
•
•
sets the DDRAM address counter to logic 0
returns the display to its original position, if it was shifted. Thus, the display
disappears and the cursor or blink position goes to the left edge of the display
sets entry mode bit I_D = 1 (increment mode); bit S of entry mode does not change
Symbol
-
-
-
Symbol
-
-
-
Clear_display bit description
Return_home bit description
Rev. 05 — 13 August 2009
Value
0
0
00000001
Value
0
0
00000010
Description
see
fixed value
Description
see
fixed value
Table 10
Table 10
Section
LCD controllers/drivers
PCF2119x
© NXP B.V. 2009. All rights reserved.
10.2.2.3). Only bit
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