A96G150 User's manual
15. Combination of USART, SPI, and I2C (USI)
187
The next figure illustrates the sampling process of the start bit of an incoming frame. The sampling rate
is 16 times of the baud-rate in normal mode and 8 times the baud-rate for double speed mode
(DBLSn=1). The horizontal arrows show the synchronization variation due to the asynchronous
sampling process. Note that larger time variation is shown when using the double speed mode.
Figure 84. Asynchronous Start Bit Sampling (USIn)
When the receiver is enabled (RXEn=1), the clock recovery logic tries to find a high-to-low transition on
the RXDn line, the start bit condition. After detecting high to low transition on RXDn line, the clock
recovery logic uses samples 8, 9 and 10 for normal mode to decide if a valid start bit is received. If more
than 2 samples have logical low level, it is considered that a valid start bit is detected and the internally
generated clock is synchronized to the incoming data frame. And the data recovery can begin. The
synchronization process is repeated for each start bit.
As described above, when the receiver clock is synchronized to the start bit, the data recovery can
begin. Data recovery process is almost same to the clock recovery process. The data recovery logic
samples 16 times for each incoming bits for normal mode and 8 times for double speed mode, and uses
sample 8, 9 and 10 to decide data value. If more than 2 samples have low levels, the received bit is
considered to a logic ‘0’ and if more than 2 samples have high le
vels, the received bit is considered to
a logic
‘1’.
RXDn
0
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
1
2
3
IDLE
BIT0
START
0
1
2
3
4
5
6
7
8
1
2
Sample
(DBLSn = 0)
Sample
(DBLSn = 1)
Содержание A96G150
Страница 126: ...12 Timer 0 1 2 3 4 5 A96G150 User s manual 126 Figure 43 16 bit Timer Counter Mode Operation Example...
Страница 136: ...12 Timer 0 1 2 3 4 5 A96G150 User s manual 136 Figure 51 16 bit Timer Counter Mode Operation Example...
Страница 147: ...A96G150 User s manual 12 Timer 0 1 2 3 4 5 147 Figure 59 16 bit Timer Counter Mode Operation Example...
Страница 157: ...A96G150 User s manual 12 Timer 0 1 2 3 4 5 157 Figure 67 16 bit Timer Counter Mode Operation Example...
Страница 171: ...A96G150 User s manual 14 12 bit ADC 171 Figure 79 ADC Operation Flow Sequence...
Страница 333: ...A96G150 User s manual Revision history 333 Revision history Revision Date Notes 1 00 2022 06 22 First creation...