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6384DS–ATARM–13-Jan-10
AT91SAM9G20 Summary
Figure 9-3.
AT91SAM9G20 Power Management Controller Block Diagram
9.6
Periodic Interval Timer
Includes a 20-bit Periodic Counter, with less than 1 s accuracy
Includes a 12-bit Interval Overlay Counter
Real Time OS or Linux/Windows CE compliant tick generator
9.7
Watchdog Timer
16-bit key-protected only-once-Programmable Counter
Windowed, prevents the processor being in a dead-lock on the watchdog access
9.8
Real-time Timer
Real-time Timer 32-bit free-running back-up Counter
Integrates a 16-bit programmable prescaler running on slow clock
Alarm Register capable of generating a wake-up of the system through the Shutdown
Controller
9.9
General-purpose Back-up Registers
Four 32-bit backup general-purpose registers
9.10
Advanced Interrupt Controller
Controls the interrupt lines (nIRQ and nFIQ) of the ARM Processor
Thirty-two individually maskable and vectored interrupt sources
MCK
periph_clk[..]
int
SLCK
MAINCK
PLLACK
Prescaler
/1,/2,/4,.../64
PCK
Processor
Clock
Controller
Idle Mode
Master Clock Controller
Peripherals
Clock Controller
ON/OFF
PLLBCK
Divider
/1,/2,/4,/6
USB Clock Controller
SLCK
MAINCK
PLLACK
Prescaler
/1,/2,/4,...,/64
Programmable Clock Controller
PLLBCK
Divider
/1,/2,/4
pck[..]
PLLBCK
UDPCK
ON/OFF
/1,/2
Divider