AT91SAM9R64-CU-999 Atmel, AT91SAM9R64-CU-999 Datasheet - Page 256

• Manufacturer Part Number: AT91SAM9R64-CU-999
• Description: IC MCU ARM9 64K SRAM 144LFBGA
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM9R64-CU-999

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 240MHz
• Connectivity: EBI/EMI, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: AC'97, POR, PWM, WDT
• Number Of I /o: 49
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: ROM
• Ram Size: 72K x 8
• Voltage - Supply (vcc/vdd): 1.08 V ~ 1.32 V
• Data Converters: A/D 3x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 144-LFBGA
• Processor Series: AT91SAMx
• Core: ARM926EJ-S
• Data Bus Width: 32 bit
• Data Ram Size: 64 KB
• Interface Type: SPI, TWI, UART
• Maximum Clock Frequency: 240 MHz
• Number Of Programmable I/os: 118
• Operating Supply Voltage: 1.65 V to 3.6 V
• 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, AT91SAM9RL-EK
• Minimum Operating Temperature: - 40 C
• For Use With: AT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

26.4.1
26.4.2
26.4.3
256
AT91SAM9R64/RL64 Preliminary
Switching from Internal RC Oscillator to the 32,768 Hz Crystal
Bypassing the 32,768 Hz Oscillator
Switching from 32768 Hz Crystal to the Internal RC Oscillator
Figure 26-2. Slow Clock Selection
RCEN, OSC32EN,OSCSEL and OSC32BYP bits are located in the Slow Clock Control Register
(SCKCR) located at address 0xFFFFFD50 in the backed up part of the System Controller and so
are preserved while VDDBU is present.
After a VDDBU power on reset, the default configuration is RCEN=1, OSC32EN=0 and OSC-
SEL=0, allowing the system to start on the internal RC oscillator.
The programmer controls the slow clock switching by software and so must take precautions
during the switching phase.
To switch from internal RC oscillator to the 32,768 Hz crystal, the programmer must execute the
following sequence:
Following steps must be added to bypass the 32,768 Hz oscillator:
The same procedure must be followed to switch from a 32,768 Hz crystal to the internal RC
oscillator.
• Switch the master clock to a source different from slow clock (PLL or Main Oscillator) through
• Enable the 32,768 Hz oscillator by setting the bit OSC32EN to 1.
• Wait 32,768 Hz Startup Time for clock stabilization (software loop).
• Switch from internal RC to 32,768 Hz oscillator by setting the bit OSCSEL to 1.
• Wait 5 slow clock cycles for internal resynchronization.
• Disable the RC oscillator by setting the bit RCEN to 0.
• An external clock must be connected on XIN32.
• Enable the bypass path OSC32BYP bit set to 1.
• Disable the 32,768 Hz oscillator by setting the bit OSC32EN to 0.
• Switch the master clock to a source different from slow clock (PLL or Main Oscillator).
• Enable the internal RC oscillator by setting the bit RCEN to 1.
the Power Management Controller.
XOUT32
XIN32
Slow Clock
Clock Generator
Oscillator
On Chip
RC OSC
Slow Clock
SLCK
OSCSEL
OSC32EN
OSC32BYP
RCEN
6289C–ATARM–28-May-09