ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 218

• Manufacturer Part Number: ATMEGA169
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Disabling the LCD
218
ATmega169/V
In the example below we assume SEG10 and COM1 and SEG4 in COM0 are the only
segments changed from frame to frame. Data are stored in r20 and r21 for simplicity
Note:
In some application it may be necessary to disable the LCD. This is the case if the MCU
enters Power-down mode where no clock source is present.
The LCD should be completely discharged before being disabled. No DC voltage should
be left across any segment. The best way to achieve this is to use the LCD Blanking fea-
ture that drives all segment pins and common pins to GND.
When the LCD is disabled, port function is activated again. Therefore, the user must
check that port pins connected to a LCD terminal are either tri-state or output low (sink).
Assembly Code Example
C Code Example
LCD_update:
Void LCD_update(unsigned char data1, data2);
{
}
; LCD Blanking and Low power waveform are unchanged.
; Update Display memory.
sts
sts
ret
/* LCD Blanking and Low power waveform are unchanged. */
/* Update Display memory. */
LCDDR0 = data1;
LCDDR6 = data2;
1. See “About Code Examples” on page 6.
LCDDR0, r20
LCDDR6, r21
(1)
(1)
2514P–AVR–07/06