AT91RM9200-CI-002 Atmel, AT91RM9200-CI-002 Datasheet - Page 293

• Manufacturer Part Number: AT91RM9200-CI-002
• Description: IC ARM9 MCU 256 BGA
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91RM9200-CI-002

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 180MHz
• Connectivity: EBI/EMI, Ethernet, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: POR
• Number Of I /o: 122
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: ROM
• Ram Size: 48K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 256-BGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

24. System Timer (ST)
24.1
24.2
1768I–ATARM–09-Jul-09
Overview
Block Diagram
The System Timer (ST) module integrates three different free-running timers:
These timers count using the Slow Clock provided by the Power Management Controller. Typi-
cally, this clock has a frequency of 32.768 kHz, but the System Timer might be configured to
support another frequency.
The System Timer provides an interrupt line connected to one of the sources of the Advanced
Interrupt Controller (AIC). Interrupt handling requires programming the AIC before configuring
the System Timer. Usually, the System Timer interrupt line is connected to the first interrupt
source line and shares this entry with the Debug Unit (DBGU) and the Real Time Clock (RTC).
This sharing requires the programmer to determine the source of the interrupt when the source 1
is triggered.
Important features of the System Timer include:
Figure 24-1. System Timer Block Diagram
• A Period Interval Timer (PIT) that sets the time base for an operating system.
• A Watchdog Timer (WDT) with system reset capabilities in case of software deadlock.
• A Real-Time Timer (RTT) counting elapsed seconds.
• One Period Interval Timer, 16-bit Programmable Counter
• One Watchdog Timer, 16-bit Programmable Counter
• One Real-time Timer, 20-bit Free-running Counter
• Interrupt Generation on Event
Management
Controller
Power
APB
SLCK
Advanced Interrupt Controller
Periodic Interval Timer
System Timer
Real-Time Timer
Watchdog Timer
STIRQ
AT91RM9200
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