atmega3250v-8auatmega325v-8ai ATMEL Corporation, atmega3250v-8auatmega325v-8ai Datasheet - Page 159
atmega3250v-8auatmega325v-8ai
Manufacturer Part Number
atmega3250v-8auatmega325v-8ai
Description
Atmega3250 8-bit Microcontroller With In-system Programmable Flash
Manufacturer
ATMEL Corporation
Datasheet
1.ATMEGA3250V-8AUATMEGA325V-8AI.pdf
(362 pages)
- Current page: 159 of 362
- Download datasheet (7Mb)
20.3.1
2570L–AVR–08/07
Internal Clock Generation – The Baud Rate Generator
Figure 20-2. Clock Generation Logic, Block Diagram
Signal description:
operation.
Internal clock generation is used for the asynchronous and the synchronous master modes of
operation. The description in this section refers to
The USART Baud Rate Register (UBRR) and the down-counter connected to it function as a
programmable prescaler or baud rate generator. The down-counter, running at system clock
(f
the UBRRL Register is written. A clock is generated each time the counter reaches zero. This
clock is the baud rate generator clock output (= f
baud rate generator clock output by 2, 8 or 16 depending on mode. The baud rate generator out-
put is used directly by the Receiver’s clock and data recovery units. However, the recovery units
use a state machine that uses 2, 8 or 16 states depending on mode set by the state of the
UMSELn, U2Xn and DDR_XCK bits.
Table 20-1
ing the UBRR value for each mode of operation using an internally generated clock source.
osc
), is loaded with the UBRR value each time the counter has counted down to zero or when
txclk
rxclk
xcki
xcko
fosc
DDR_XCK
XCK
Pin
contains equations for calculating the baud rate (in bits per second) and for calculat-
xcko
xcki
OSC
Transmitter clock (Internal Signal).
Receiver base clock (Internal Signal).
Input from XCK pin (internal Signal). Used for synchronous slave
Clock output to XCK pin (Internal Signal). Used for synchronous master
operation.
XTAL pin frequency (System Clock).
Down-Counter
Prescaling
Register
UBRR
Sync
UBRR+1
fosc
Detector
UCPOL
Edge
/2
ATmega325/3250/645/6450
Figure
osc
/(UBRR+1)). The Transmitter divides the
/4
20-2.
/2
DDR_XCK
U2X
0
1
0
1
0
1
1
0
UMSEL
txclk
rxclk
159
Related parts for atmega3250v-8auatmega325v-8ai
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
IC AVR MCU 32K 8MHZ 100TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
IC AVR MCU 32K 8MHZ 100TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
MCU AVR 32K FLASH 8MHZ 100TQFP
Manufacturer:
Atmel
Datasheet:
Part Number:
Description:
INTERVAL AND WIPE/WASH WIPER CONTROL IC WITH DELAY
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Low-Voltage Voice-Switched IC for Hands-Free Operation
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
MONOLITHIC INTEGRATED FEATUREPHONE CIRCUIT
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
AM-FM Receiver IC U4255BM-M
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Monolithic Integrated Feature Phone Circuit
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Multistandard Video-IF and Quasi Parallel Sound Processing
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
High-performance EE PLD
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
8-bit Flash Microcontroller
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
2-Wire Serial EEPROM
Manufacturer:
ATMEL Corporation
Datasheet: