AT91SAM7X128 Atmel, AT91SAM7X128 Datasheet - Page 314

• Manufacturer Part Number: AT91SAM7X128
• Description: MCU 32-Bit 91S ARM7TDMI RISC 128KB Flash 1.8V/3.3V 100-Pin LQFP
• Manufacturer: Atmel

Specifications of AT91SAM7X128

• Package: 100LQFP
• Device Core: ARM7TDMI
• Family Name: 91S
• Maximum Speed: 55 MHz
• Ram Size: 32 KB
• Program Memory Size: 128 KB
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 62
• Interface Type: CAN/Ethernet/SPI/I2S/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 3

30.6.3.3
314
AT91SAM7X512/256/128 Preliminary
Synchronous Receiver
transmitter can occur. Moreover, as soon as the stop bit is sampled, the receiver starts looking
for a new start bit so that resynchronization can also be accomplished when the transmitter is
operating with one stop bit.
Figure 30-8
operates in asynchronous mode.
Figure 30-8. Asynchronous Start Detection
Figure 30-9. Asynchronous Character Reception
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 30-10
Clock (x16)
Baud Rate
Sampling
Sampling
Sampling
Baud Rate
Example: 8-bit, Parity Enabled
Detection
Clock
RXD
RXD
Start
Clock
RXD
and
illustrates a character reception in synchronous mode.
1
1
Figure 30-9
2
2
samples
3
3
16
4
4
D0
5
5
samples
illustrate start detection and character reception when USART
16
6
6
D1
7
Detection
7
Rejection
samples
Start
Start
16
8
0
D2
1
1
samples
16
2
2
3
3
D3
samples
4
4
16
5
D4
samples
6
16
7
D5
samples
8
16
9 10 11 12 13 14 15 16
D6
samples
16
D7
samples
16
6120H–ATARM–17-Feb-09
Parity
Bit
samples
16
Stop
Bit
Sampling
D0