SAM7L128 Atmel Corporation, SAM7L128 Datasheet - Page 395

• Manufacturer Part Number: SAM7L128
• Manufacturer: Atmel Corporation

Specifications of SAM7L128

• Flash (kbytes): 128 Kbytes
• Pin Count: 144
• Max. Operating Frequency: 36 MHz
• Cpu: ARM7TDMI
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 80
• Ext Interrupts: 80
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 3
• Segment Lcd: 40
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 460
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 6
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 1.8 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 3
• Input Capture Channels: 3
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

30.6.8
30.6.8.1
30.6.8.2
30.6.8.3
6257A–ATARM–20-Feb-08
Test Modes
Normal Mode
Automatic Echo Mode
Local Loopback Mode
The USART can be programmed to operate in three different test modes. The internal loopback
capability allows on-board diagnostics. In the loopback mode the USART interface pins are dis-
connected or not and reconfigured for loopback internally or externally.
Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD
pin.
Figure 30-38. Normal Mode Configuration
Automatic echo mode allows bit-by-bit retransmission. When a bit is received on the RXD pin, it
is sent to the TXD pin, as shown in
the TXD pin. The RXD pin is still connected to the receiver input, thus the receiver remains
active.
Figure 30-39. Automatic Echo Mode Configuration
Local loopback mode connects the output of the transmitter directly to the input of the receiver,
as shown in
the receiver and the TXD pin is continuously driven high, as in idle state.
Figure 30-40. Local Loopback Mode Configuration
Figure
30-40. The TXD and RXD pins are not used. The RXD pin has no effect on
Transmitter
Transmitter
Transmitter
Receiver
Receiver
Receiver
Figure
AT91SAM7L128/64 Preliminary
30-39. Programming the transmitter has no effect on
1
RXD
TXD
RXD
TXD
RXD
TXD
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