AT91SAM9261-CJ-999 Atmel, AT91SAM9261-CJ-999 Datasheet - Page 113

• Manufacturer Part Number: AT91SAM9261-CJ-999
• Description: IC MCU ARM9 ULTRA LP 217LFBGA
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM9261-CJ-999

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 190MHz
• Connectivity: EBI/EMI, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: DMA, LCD, POR, PWM, WDT
• Number Of I /o: 96
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: ROM
• Ram Size: 192K x 8
• Voltage - Supply (vcc/vdd): 1.08 V ~ 1.32 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 217-LFBGA
• For Use With: AT91SAM9261-EK - KIT EVAL FOR AT91SAM926EJ-SAT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -

16. Periodic Interval Timer (PIT)
16.1
16.2
Figure 16-1. Periodic Interval Timer
16.3
6062M–ATARM–23-Mar-09
Prescaler
MCK
Overview
Block Diagram
Functional Description
MCK/16
The Periodic Interval Timer (PIT) provides the operating system’s scheduler interrupt. It is
designed to offer maximum accuracy and efficient management, even for systems with long
response time .
The Periodic Interval Timer aims at providing periodic interrupts for use by operating systems.
The PIT provides a programmable overflow counter and a reset-on-read feature. It is built
around two counters: a 20-bit CPIV counter and a 12-bit PICNT counter. Both counters work at
Master Clock /16.
The first 20-bit CPIV counter increments from 0 up to a programmable overflow value set in the
field PIV of the Mode Register (PIT_MR). When the counter CPIV reaches this value, it resets to
0 and increments the Periodic Interval Counter, PICNT. The status bit PITS in the Status Regis-
ter (PIT_SR) rises and triggers an interrupt, provided the interrupt is enabled (PITIEN in
PIT_MR).
Counter
0
CPIV
CPIV
20-bit
0
1
PIT_PIVR
PIT_PIIR
PIT_MR
= ?
PIV
0
AT91SAM9261 Preliminary
0
PICNT
Adder
12-bit
PICNT
1
PIT_SR
read PIT_PIVR
PITS
set
reset
PIT_MR
PITIEN
pit_irq
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