ATmega645P Atmel Corporation, ATmega645P Datasheet - Page 177
![no-image](/images/manufacturer_photos/0/0/79/atmel_corporation_sml.jpg)
ATmega645P
Manufacturer Part Number
ATmega645P
Description
Manufacturer
Atmel Corporation
Specifications of ATmega645P
Flash (kbytes)
64 Kbytes
Pin Count
64
Max. Operating Frequency
16 MHz
Cpu
8-bit AVR
# Of Touch Channels
16
Hardware Qtouch Acquisition
No
Max I/o Pins
54
Ext Interrupts
17
Usb Speed
No
Usb Interface
No
Spi
2
Twi (i2c)
1
Uart
1
Graphic Lcd
No
Video Decoder
No
Camera Interface
No
Adc Channels
8
Adc Resolution (bits)
10
Adc Speed (ksps)
15
Analog Comparators
1
Resistive Touch Screen
No
Temp. Sensor
No
Crypto Engine
No
Sram (kbytes)
4
Eeprom (bytes)
2048
Self Program Memory
YES
Dram Memory
No
Nand Interface
No
Picopower
Yes
Temp. Range (deg C)
-40 to 85
I/o Supply Class
1.8 to 5.5
Operating Voltage (vcc)
1.8 to 5.5
Fpu
No
Mpu / Mmu
no / no
Timers
3
Output Compare Channels
4
Input Capture Channels
1
Pwm Channels
4
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
- Current page: 177 of 679
- Download datasheet (37Mb)
20.6
20.6.1
20.6.2
8285D–AVR–06/11
Data Transmission – The USART Transmitter
Sending Frames with 5 to 8 Data Bit
Sending Frames with 9 Data Bit
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P
The USART Transmitter is enabled by setting the Transmit Enable (TXENn) bit in the UCSRnB
Register. When the Transmitter is enabled, the normal port operation of the TxD pin is overrid-
den by the USART and given the function as the Transmitter’s serial output. The baud rate,
mode of operation and frame format must be set up once before doing any transmissions. If syn-
chronous operation is used, the clock on the XCK pin will be overridden and used as
transmission clock.
A data transmission is initiated by loading the transmit buffer with the data to be transmitted. The
CPU can load the transmit buffer by writing to the UDRn I/O location. The buffered data in the
transmit buffer will be moved to the Shift Register when the Shift Register is ready to send a new
frame. The Shift Register is loaded with new data if it is in idle state (no ongoing transmission) or
immediately after the last stop bit of the previous frame is transmitted. When the Shift Register is
loaded with new data, it will transfer one complete frame at the rate given by the Baud Register,
U2Xn bit or by XCK depending on mode of operation.
The following code examples show a simple USART transmit function based on polling of the
Data Register Empty (UDREn) Flag. When using frames with less than eight bits, the most sig-
nificant bits written to the UDRn are ignored. The USART has to be initialized before the function
can be used. For the assembly code, the data to be sent is assumed to be stored in Register
R16.
Note:
The function simply waits for the transmit buffer to be empty by checking the UDREn Flag,
before loading it with new data to be transmitted. If the Data Register Empty interrupt is utilized,
the interrupt routine writes the data into the buffer.
If 9-bit characters are used (UCSZ = 7), the ninth bit must be written to the TXB8n bit in
UCSRnB before the low byte of the character is written to UDRn. The following code examples
Assembly Code Example
C Code Example
USART_Transmit:
void USART_Transmit( unsigned char data )
{
}
; Wait for empty transmit buffer
sbis UCSR0A,UDREn
rjmp USART_Transmit
; Put data (r16) into buffer, sends the data
sts
ret
/* Wait for empty transmit buffer */
while ( !( UCSR0A & (1<<UDRE0)) )
/* Put data into buffer, sends the data */
UDR0 = data;
1.
See ”About Code Examples” on page 9.
UDR0,r16
;
(1)
(1)
177
Related parts for ATmega645P
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![U641B](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
INTERVAL AND WIPE/WASH WIPER CONTROL IC WITH DELAY
Manufacturer:
ATMEL Corporation
Datasheet:
![U4082B](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Low-Voltage Voice-Switched IC for Hands-Free Operation
Manufacturer:
ATMEL Corporation
Datasheet:
![U4089B](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
MONOLITHIC INTEGRATED FEATUREPHONE CIRCUIT
Manufacturer:
ATMEL Corporation
Datasheet:
![U4255BM-M](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
AM-FM Receiver IC U4255BM-M
Manufacturer:
ATMEL Corporation
Datasheet:
![U4089B-P](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Monolithic Integrated Feature Phone Circuit
Manufacturer:
ATMEL Corporation
Datasheet:
![TDA4470](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Multistandard Video-IF and Quasi Parallel Sound Processing
Manufacturer:
ATMEL Corporation
Datasheet:
![ATF22V10B-25PC](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
High-performance EE PLD
Manufacturer:
ATMEL Corporation
Datasheet:
![AT89C51ED2-IM](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
8-bit Flash Microcontroller
Manufacturer:
ATMEL Corporation
Datasheet:
![AT24C01](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
2-Wire Serial EEPROM
Manufacturer:
ATMEL Corporation
Datasheet:
![U6046B](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
U6046BREAR WINDOW HEATING TIMER / LONG-TERM TIMER
Manufacturer:
ATMEL Corporation
Datasheet: