AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 187

• Manufacturer Part Number: AT91SAM7S256D-AU
• Description: ARM Microcontrollers - MCU 256K Flash SRAM 64K ARM based MCU
• Manufacturer: Atmel
• Series: SAM7S256r

Specifications of AT91SAM7S256D-AU

• Rohs: yes
• Core: ARM
• Processor Series: AT91SAM
• Data Bus Width: 16 bit/32 bit
• Maximum Clock Frequency: 55 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3 V to 3.6 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: LQFP-64
• Mounting Style: SMD/SMT
• Interface Type: 2-Wire, I2S, SPI, USART
• Length: 7 mm

24. Clock Generator
24.1
24.2
24.3
24.3.1
Overview
The Clock Generator is made up of 1 PLL, a Main Oscillator, as well as an RC Oscillator.
It provides the following clocks:
The Clock Generator User Interface is embedded within the Power Management Controller one and is described in
Section
Slow Clock RC Oscillator
The user has to take into account the possible drifts of the RC Oscillator. More details are given in the section “DC
Characteristics” of the product datasheet.
Main Oscillator
Figure 24-1
Figure 24-1. Main Oscillator Block Diagram
The Clock Generator integrates a Main Oscillator that is designed for a 3 to 20 MHz fundamental crystal. The typi-
cal crystal connection is illustrated in
Oscillator, see the section “DC Characteristics” of the product datasheet.
• SLCK, the Slow Clock, which is the only permanent clock within the system
• MAINCK is the output of the Main Oscillator
• PLLCK is the output of the Divider and PLL block
Main Oscillator Connections
25.9. However, the Clock Generator registers are named CKGR_.
shows the Main Oscillator block diagram.
Slow Clock
XOUT
SLCK
XIN
Figure
24-2. For further details on the electrical characteristics of the Main
Main Clock
OSCOUNT
Frequency
Oscillator
MOSCEN
Oscillator
Counter
Counter
Main
Main
Main Clock
MAINCK
MAINRDY
SAM7S Series [DATASHEET]
MOSCS
MAINF
6175M–ATARM–26-Oct-12
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