ATMEGA644V-10MUR Atmel, ATMEGA644V-10MUR Datasheet - Page 192

• Manufacturer Part Number: ATMEGA644V-10MUR
• Description: MCU AVR 64K FLASH 10MHZ 44QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644V-10MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 10MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• 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: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18.4
192
SPI Data Modes and Timing
ATmega644
Table 18-1.
Note:
There are four combinations of XCKn (SCK) phase and polarity with respect to serial data, which
are determined by control bits UCPHAn and UCPOLn. The data transfer timing diagrams are
shown in
signal, ensuring sufficient time for data signals to stabilize. The UCPOLn and UCPHAn function-
ality is summarized in
all ongoing communication for both the Receiver and Transmitter.
Table 18-2.
Figure 18-1. UCPHAn and UCPOLn data transfer timing diagrams.
Operating Mode
Synchronous Master
mode
UCPOLn
BAUD
f
UBRRn
OSC
Data setup (TXD)
XCK
Data sample (RXD)
XCK
Data setup (TXD)
Data sample (RXD)
0
0
1
1
1. The baud rate is defined to be the transfer rate in bit per second (bps)
Figure
Equations for Calculating Baud Rate Register Setting
UCPOLn and UCPHAn Functionality-
18-1. Data bits are shifted out and latched in on opposite edges of the XCKn
UCPHAn
Table
Baud rate (in bits per second, bps)
System Oscillator clock frequency
Contents of the UBRRnH and UBRRnL Registers, (0-4095)
0
1
0
1
UCPOL=0
Equation for Calculating Baud
18-2. Note that changing the setting of any of these bits will corrupt
BAUD
SPI Mode
=
0
1
2
3
Rate
-------------------------------------- -
2 UBRRn
(
(1)
f
OSC
Leading Edge
Sample (Rising)
Setup (Rising)
Sample (Falling)
Setup (Falling)
+
XCK
Data setup (TXD)
Data sample (RXD)
XCK
Data setup (TXD)
Data sample (RXD)
1
)
Equation for Calculating UBRRn
UBRRn
UCPOL=1
Trailing Edge
Setup (Falling)
Sample (Falling)
Setup (Rising)
Sample (Rising)
Value
=
------------------- - 1
2BAUD
f
OSC
2593N–AVR–07/10
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