AT91M40800-33AU Atmel, AT91M40800-33AU Datasheet - Page 59

• Manufacturer Part Number: AT91M40800-33AU
• Description: IC ARM7 MCU 100 LQFP
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91M40800-33AU

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 33MHz
• Connectivity: EBI/EMI, UART/USART
• Peripherals: POR, WDT
• Number Of I /o: 32
• Program Memory Type: ROMless
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-LQFP
• Package: 100TQFP
• Device Core: ARM7TDMI
• Family Name: 91M
• Maximum Speed: 33 MHz
• Operating Supply Voltage: 2.5|3.3 V
• Data Bus Width: 32 Bit
• Number Of Programmable I/os: 32
• Interface Type: EBI/USART
• Number Of Timers: 3
• Processor Series: AT91Mx
• Core: ARM7TDMI
• Data Ram Size: 8 KB
• Maximum Clock Frequency: 33 MHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: JTRACE-ARM-2M, MDK-ARM, RL-ARM, ULINK2
• Minimum Operating Temperature: - 40 C
• Eeprom Memory: 0 Bytes
• Input Output: 32
• Interface: EBI/EMI, UART/USART
• Ios: 32
• Memory Type: ROMless
• Number Of Bits: 32
• Package Type: 100-pin LQFP
• Programmable Memory: 0 Bytes
• Timers: 3-16-bit
• Voltage, Range: 1.8-3.6 V
• Cpu Family: 91M
• Device Core Size: 32b
• Frequency (max): 33MHz
• Program Memory Size: Not Required
• Total Internal Ram Size: 8KB
• # I/os (max): 32
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 2.5/3.3V
• Operating Supply Voltage (max): 3.6V
• Operating Supply Voltage (min): 1.8V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 100
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Interrupt Clearing and
Setting
Fast Interrupt Request
Software Interrupt
Spurious Interrupt
1354D–ATARM–08/02
All interrupt sources which are programmed to be edge triggered (including FIQ) can be
individually set or cleared by respectively writing to the registers AIC_ISCR and
AIC_ICCR. This function of the interrupt controller is available for auto-test or software
debug purposes.
The external FIQ line is the only source which can raise a fast interrupt request to the
processor. Therefore, it has no priority controller.
The external FIQ line can be programmed to be positive or negative edge triggered or
high- or low-level sensitive in the AIC_SMR0 register.
The fast interrupt handler address can be stored in the AIC_SVR0 register. The value
written into this register is available by reading the AIC_FVR register when an FIQ inter-
rupt is raised. By storing the following instruction at address 0x0000001C, the processor
will load the program counter with the interrupt handler address stored in the AIC_FVR
register.
Alternatively the interrupt handler can be stored starting from address 0x0000001C as
described in the ARM7TDMI datasheet.
Interrupt source 1 of the advanced interrupt controller is a software interrupt. It must be
programmed to be edge triggered in order to set or clear it by writing to the AIC_ISCR
and AIC_ICCR.
This is totally independent of the SWI instruction of the ARM7TDMI processor.
When the AIC asserts the NIRQ line, the ARM7TDMI enters IRQ Mode and the interrupt
handler reads the IVR. It may happen that the AIC de-asserts the NIRQ line after the
core has taken into account the NIRQ assertion and before the read of the IVR.
This behavior is called a Spurious Interrupt.
The AIC is able to detect these Spurious Interrupts and returns the Spurious Vector
when the IVR is read. The Spurious Vector can be programmed by the user when the
vector table is initialized.
A spurious interrupt may occur in the following cases:
•
•
The same mechanism of spurious interrupt occurs if the ARM7TDMI reads the IVR
(application software or ICE) when there is no interrupt pending. This mechanism is also
valid for the FIQ interrupts.
Once the AIC enters the spurious interrupt management, it asserts neither the NIRQ nor
the NFIQ lines to the ARM7TDMI as long as the spurious interrupt is not acknowledged.
Therefore, it is mandatory for the Spurious Interrupt Service Routine to acknowledge the
“spurious” behavior by writing to the AIC_EOICR (End of Interrupt) before returning to
the interrupted software. It also can perform other operation(s), e.g., trace possible
undesirable behavior.
ldr PC,[PC,# -&F20]
With any sources programmed to be level sensitive, if the interrupt signal of the AIC
input is de-asserted at the same time as it is taken into account by the ARM7TDMI.
If an interrupt is asserted at the same time as the software is disabling the
corresponding source through AIC_IDCR (this can happen due to the pipelining of
the ARM core).
AT91X40 Series
59