ATMEGA329P-20MN Atmel, ATMEGA329P-20MN Datasheet - Page 245

• Manufacturer Part Number: ATMEGA329P-20MN
• Description: IC MCU AVR 32K 20MHZ 64QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA329P-20MN

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-MLF®, 64-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

23.5.4
8021G–AVR–03/11
LCDCCR – LCD Contrast Control Register
is increased with 33% when Frame Rate Register is constant. Example of frame rate calculation
is shown in
Table 23-6.
• Bits 7:5 – LCDDC2:0: LDC Display Configuration
The LCDDC2:0 bits determine the amount of time the LCD drivers are turned on for each volt-
age transition on segment and common pins. A short drive time will lead to lower power
consumption, but displays with high internal resistance may need longer drive time to achieve
satisfactory contrast. Note that the drive time will never be longer than one half prescaled LCD
clock period, even if the selected drive time is longer. When using static duty or blanking, drive
time will always be one half prescaled LCD clock period.
New values take effect immediately, and can cause small glitches in the display output. This can
be avoided by setting the LCDBL in LCDCRA, and wait to the next start of frame before chang-
ing LCDDC2:0.
Table 23-7.
Note:
• Bit 4 – LCDMDT: LCD Maximum Drive Time
Writing this bit to one turns the LCD drivers on 100% all the time, regardless of the drive time
configured by LCDDC2:0.
Bit
(0xE7)
Read/Write
Initial Value
clk
4MHz
4MHz
32.768kHz
32.768kHz
LCD
LCDDC2
The drive time will be longer dependent on oscillator startup time.
0
0
0
0
1
1
1
1
Table 23-6 on page
LCDDC2
Example of frame rate calculation
LCD Display Configuration
R/W
duty
7
0
Static
1/4
1/3
1/2
LCDDC1
R/W
K
8
6
8
8
6
0
LCDDC1
0
0
1
1
0
0
1
1
245.
LCDDC0
2048
2048
R/W
16
16
5
0
N
LCDNDT
R
4
0
LCDCD2:0
011
011
000
100
LCDDC0
LCDCC3
0
1
0
1
0
1
0
1
R/W
3
0
ATmega329P/3290P
D
4
4
1
5
LCDCC2
R/W
2
0
Nominal drive time
300µs
70µs
150µs
450µs
575µs
850µs
1150µs
50% of clk
Frame Rate
4000000/(8*2048*4) = 61Hz
4000000/(6*2048*4) = 81Hz
32768/(8*16*1) = 256Hz
32768/(8*16*5) = 51Hz
LCDCC1
R/W
1
0
LCD_PS
LCDCC0
R/W
0
0
LCDCCR
245