SAM7S256_14 Datasheet, PDF (371/775 Pages) ATMEL Corporation – ARM-based Flash MCU

Figure 31-10. Asynchronous Start Detection
Baud Rate
Clock
Sampling
Clock (x16)
RXD
Sampling
RXD
Sampling
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
D0
Start
Sampling
Detection
123456701234
Start
Rejection
Figure 31-11. Asynchronous Character Reception
Example: 8-bit, Parity Enabled
Baud Rate
Clock
RXD
Start
Detection
16
16
16
16
16
16
16
16
16
16
samples samples samples samples samples samples samples samples samples samples
D0 D1 D2 D3 D4 D5 D6 D7 Parity Stop
Bit Bit
31.6.3.3 Synchronous Receiver
In synchronous mode (SYNC = 1), the receiver samples the RXD signal on each rising edge of the Baud Rate
Clock. If a low level is detected, it is considered as a start. All data bits, the parity bit and the stop bits are sampled
and the receiver waits for the next start bit. Synchronous mode operations provide a high speed transfer capability.
Configuration fields and bits are the same as in asynchronous mode.
Figure 31-12 illustrates a character reception in synchronous mode.
Figure 31-12. Synchronous Mode Character Reception
Example: 8-bit, Parity Enabled 1 Stop
Baud Rate
Clock
RXD
Sampling
Start D0 D1 D2 D3 D4 D5 D6 D7
Stop Bit
Parity Bit
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
371