AT90PWM216-16SE ATMEL [ATMEL Corporation], AT90PWM216-16SE Datasheet - Page 199
AT90PWM216-16SE
Manufacturer Part Number
AT90PWM216-16SE
Description
8-bit Microcontroller with 16K Bytes In-System Programmable flash
Manufacturer
ATMEL [ATMEL Corporation]
Datasheet
1.AT90PWM216-16SE.pdf
(360 pages)
- Current page: 199 of 360
- Download datasheet (6Mb)
18.8
18.8.1
7710D–AVR–08/09
Asynchronous Data Reception
Asynchronous Clock Recovery
Note:
The USART includes a clock recovery and a data recovery unit for handling asynchronous data
reception. The clock recovery logic is used for synchronizing the internally generated baud rate
clock to the incoming asynchronous serial frames at the RxD pin. The data recovery logic sam-
ples and low pass filters each incoming bit, thereby improving the noise immunity of the
Receiver. The asynchronous reception operational range depends on the accuracy of the inter-
nal baud rate clock, the rate of the incoming frames, and the frame size in number of bits.
The clock recovery logic synchronizes internal clock to the incoming serial frames.
illustrates the sampling process of the start bit of an incoming frame. The sample rate is 16 times
the baud rate for Normal mode, and eight times the baud rate for Double Speed mode. The hor-
izontal arrows illustrate the synchronization variation due to the sampling process. Note the
larger time variation when using the Double Speed mode (U2X = 1) of operation. Samples
denoted zero are samples done when the RxD line is idle (i.e., no communication activity).
Figure 18-6. Start Bit Sampling
When the clock recovery logic detects a high (idle) to low (start) transition on the RxD line, the
start bit detection sequence is initiated. Let sample 1 denote the first zero-sample as shown in
the figure. The clock recovery logic then uses samples 8, 9, and 10 for Normal mode, and sam-
Assembly Code Example
C Code Example
TABLE 2.
USART_Flush:
void USART_Flush( void )
{
}
sbis UCSRA, RXC0
ret
lds
rjmp USART_Flush
unsigned char dummy;
while ( UCSRA & (1<<RXC0) ) dummy = UDR;
1. The example code assumes that the part specific header file is included.
(U2Xn = 0)
(U2Xn = 1)
For I/O Registers located in extended I/O map, “IN”, “OUT”, “SBIS”, “SBIC”, “CBI”, and “SBI”
instructions must be replaced with instructions that allow access to extended I/O. Typically
“LDS” and “STS” combined with “SBRS”, “SBRC”, “SBR”, and “CBR”.
Sample
Sample
RxDn
r16, UDR
(1)
0
0
IDLE
0
(1)
1
1
2
3
2
4
5
3
6
7
4
8
START
9
5
10
AT90PWM216/316
11
6
12
13
7
14
15
8
16
1
1
Figure 18-6
2
BIT 0
3
2
199
Related parts for AT90PWM216-16SE
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
At90pwm2 8-bit Avr Microcontroller With 8k Bytes In-system Programmable Flash
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Atmel CryptoMemory
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
Atmel CryptoMemory
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
Atmel CryptoMemory, 16Kbit
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
8-bit Atmel Microcontrollers
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
8-bit Atmel Microcontroller with 64K/128K/256K Bytes In-System Programmable Flash
Manufacturer:
ATMEL [ATMEL Corporation]
Datasheet:
Part Number:
Description:
8-bit Atmel Microcontroller with 16/32/64/128K Bytes In-System Programmable Flash
Manufacturer:
ATMEL [ATMEL Corporation]
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: