AT91R40807 Datasheet, PDF (12/19 Pages) ATMEL Corporation – AT91 ARM Thumb Microcontrollers

System Peripherals
PS: Power-saving
AIC: Advanced Interrupt
Controller
PIO: Parallel I/O Controller
WD: Watchdog
SF: Special Function
The Power-saving feature optimizes power consumption, enabling the software to stop
the ARM7TDMI clock (idle mode), restarting it when the module receives an interrupt (or
reset). It also enables on-chip peripheral clocks to be enabled and disabled individually,
matching power consumption and application need.
The Advanced Interrupt Controller has an 8-level priority, individually maskable, vec-
tored interrupt controller, and drives the NIRQ and NFIQ pins of the ARM7TDMI from:
• The external fast interrupt line (FIQ)
• The three external interrupt request lines (IRQ0-IRQ2)
• The interrupt signals from the on-chip peripherals.
The AIC is largely programmable offering maximum flexibility, and its vectoring features
reduce the real-time overhead in handling interrupts.
The AIC also features a spurious vector, which reduces spurious interrupt handling to a
minimum, and a protect mode that facilitates the debug capabilities.
The AT91R40807 microcontroller has 32 programmable I/O lines. Six pins are dedi-
cated as general-purpose I/O pins. Other I/O lines are multiplexed with an external
signal of a peripheral to optimize the use of available package pins. The PIO controller
enables generation of an interrupt on input change and insertion of a simple input glitch
filter on any of the PIO pins.
The Watchdog is built around a 16-bit counter and is used to prevent system lock-up if
the software becomes trapped in a deadlock. It can generate an internal reset or inter-
rupt, or assert an active level on the dedicated pin NWDOVF. All programming registers
are password-protected to prevent unintentional programming.
The AT91R40807 microcontroller provide registers that implement the following special
functions.
• Chip identification
• RESET status
• Protect mode
• Write protection for the AT91R40807 internal 128-Kbyte memory
12 AT91R40807
1345DS–ATARM–02/02