ATMEGA649-16MI Atmel, ATMEGA649-16MI Datasheet - Page 242

• Manufacturer Part Number: ATMEGA649-16MI
• Description: IC AVR MCU FLASH 64K 5V 64QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA649-16MI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K 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: Contains lead / RoHS non-compliant

242
ATmega329/3290/649/6490
Table 23-5.
The frame frequency can be calculated by the following equation:
Where:
This is a very flexible scheme, and users are encouraged to calculate their own table to investi-
gate the possible frame rates from the formula above. Note when using 1/3 duty the frame rate
is increased with 33% when Frame Rate Register is constant. Example of frame rate calculation
is shown in
Table 23-6.
clk
4MHz
4MHz
32.768kHz
32.768kHz
LCDCD2
LCD
0
0
0
0
1
1
1
1
N = prescaler divider (16, 64, 128, 256, 512, 1024, 2048, or 4096).
K = 8 for duty = 1/4, 1/2, and static.
K = 6 for duty = 1/3.
D = Division factor (see
Table
LCDCD1
duty
1/4
1/3
Static
1/2
LCD Clock Divide
Example of frame rate calculation
0
0
1
1
0
0
1
1
23-6.
K
8
6
8
8
LCDCD0
0
1
0
1
0
1
0
1
Table
2048
2048
16
16
N
divided by (D) :
Output from
23-5)
Prescaler
f
LCDCD2:0
frame
1
2
3
4
5
6
7
8
011
011
000
100
=
------------------------- -
(
K N D
f
clk
⋅
Duty = 1/4, gives a frame rate of:
LCD
clk
D
4
4
1
5
⋅
LCD
)
Frame Rate
4000000/(8*2048*4) = 61 Hz
4000000/(6*2048*4) = 81 Hz
32768/(8*16*1) = 256 Hz
32768/(8*16*5) = 51 Hz
= 32.768kHz, N = 16, and
85.3Hz
51.2Hz
42.7Hz
36.6Hz
256Hz
128Hz
64Hz
32Hz
2552K–AVR–04/11