AT91SAM7L128-CU Atmel, AT91SAM7L128-CU Datasheet - Page 214

• Manufacturer Part Number: AT91SAM7L128-CU
• Description: MCU ARM7 128K HS FLASH 144-LFBGA
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM7L128-CU

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 36MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 80
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Ram Size: 6K x 8
• Voltage - Supply (vcc/vdd): 1.55 V ~ 1.8 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 144-LFBGA
• Processor Series: AT91SAMx
• Core: ARM7TDMI
• Data Bus Width: 32 bit
• Data Ram Size: 6 KB
• Interface Type: 2-Wire, SPI, USART
• Maximum Clock Frequency: 36 MHz
• Number Of Programmable I/os: 80
• Number Of Timers: 3
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: JTRACE-ARM-2M, MDK-ARM, RL-ARM, ULINK2
• Development Tools By Supplier: AT91SAM-ICE, AT91-ISP, AT91SAM7L-EK
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 4 Channel
• For Use With: AT91SAM7L-STK - KIT EVAL FOR AT91SAM7LAT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

24.2
24.3
24.4
214
Slow Clock
Slow Clock RC Oscillator
Slow Clock Crystal Oscillator
AT91SAM7L128/64 Preliminary
The Slow Clock is generated by the Slow Clock Crystal Oscillator or by the Slow Clock RC
Oscillator.
The selection is made by writing the XTALSEL bit in the Supply Controller Control Register
(SUPC_CR).
By default, the RC Oscillator is selected.
By default, the Slow Clock RC Oscillator is enabled and selected. The user has to take into
account the possible drifts of the RC Oscillator. More details are given in the section “DC Char-
acteristics” of the product datasheet.
It can be disabled via the XTALSEL bit in the Supply Controller Control Register (SUPC_CR).
The Clock Generator integrates a 32,768 Hz low-power oscillator.The XIN and XOUT pins must
be connected to a 32,768 Hz crystal. Two external capacitors must be wired as shown in
24-2.More details are given in the section “DC Characteristics” of the product datasheet.
Note that the user is not obliged to use the Slow Clock Crystal and can use the RC Oscillator
instead. In this case, XIN and XOUT can be left unconnected.
Figure 24-2. Typical Slow Clock Crystal Oscillator Connection
The user can set the Slow Clock Crystal Oscillator in bypass mode instead of connecting a crys-
tal. In this case, the user has to provide the external clock signal on XIN. The input
characteristics of the XIN pin under these conditions are given in the product electrical charac-
teristics section.
The programmer has to be sure to set the OSCBYPASS bit in the Supply Controller Mode Reg-
ister (SUPC_MR) and XTALSEL bit in the Supply Controller Control Register (SUPC_CR).
XIN
32,768 Hz
Crystal
XOUT
GND
6257A–ATARM–20-Feb-08
Figure