ATMEGA649V-8AI Atmel, ATMEGA649V-8AI Datasheet - Page 229

• Manufacturer Part Number: ATMEGA649V-8AI
• Description: IC AVR MCU FLASH 64K 1.8V 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA649V-8AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• 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): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

23.1.3
23.1.4
23.1.5
2552K–AVR–04/11
LCD Clock Sources
LCD Prescaler
LCD Memory
Figure 23-1. LCD Module Block Diagram
The LCD Controller can be clocked by an internal synchronous or an external asynchronous
clock source. The clock source clk
LCDCS bit in the LCDCRB Register is written to logic one, the clock source is taken from the
TOSC1 pin.
The clock source must be stable to obtain accurate LCD timing and hence minimize DC voltage
offset across LCD segments.
The prescaler consist of a 12-bit ripple counter and a 1- to 8-clock divider. The LCDPS2:0 bits
selects clk
If a finer resolution rate is required, the LCDCD2:0 bits can be used to divide the clock further by
1 to 8.
Output from the clock divider clk
The display memory is available through I/O Registers grouped for each common terminal.
When a bit in the display memory is written to one, the corresponding segment is energized (on),
and non-energized when a bit in the display memory is written to zero.
D
A
T
A
B
U
S
LCD
divided by 16, 64, 128, 256, 512, 1024, 2048, or 4096.
LCDCRA
LCDCRB
LCDCCR
LCDFRR
LCDDR 19 -15
LCDDR 14 -10
TOSC
LCDDR 9 - 5
LCDDR 4 - 0
clk
i/o
lcdcc3:0
lcddc2:0
0
1
lcdcs
LATCH
array
LCD_PS
LCD Display Configuration
clk
LCD
Contrast Controller/
LCD
Power Supply
lcdps2:0
lcdcd2:0
is used as clock source for the LCD timing.
is by default equal to the system clock, clk
MUX
40 x
4:1
ATmega329/3290/649/6490
Divide by 1 to 8
12-bit Prescaler
LCD_voltage_ok
Multiplexer
LCD Ouput
Decoder
Timing
Clock
LCD
clk
LCD_PS
LCD Buffer/
Driver
CAP
LCD
1/3 V
1/2 V
2/3 V
V
LCD
LCD
LCD
LCD
Analog
Switch
Array
I/O
SEG35
SEG36
SEG37
SEG38
SEG39
COM0
COM1
COM2
COM3
SEG0
SEG1
SEG2
SEG3
SEG4
SEG5
. When the
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