AT43USB355M-AC ATMEL [ATMEL Corporation], AT43USB355M-AC Datasheet - Page 21

• Manufacturer Part Number: AT43USB355M-AC
• Description: Full-speed USB Microcontroller with Embedded Hub, ADC and PWM
• Manufacturer: ATMEL [ATMEL Corporation]

2603G–USB–04/06
The most typical and general program setup for the Reset and Interrupt Vector Addresses are:
USB related interrupt events are routed to reset vectors 13 and 2 through a separate set of
interrupt, interrupt enable and interrupt mask registers that are mapped to the data SRAM
space. These interrupts must be enabled though their control register bits. In the event an
interrupt is generated, the source of the interrupt is identified by reading the interrupt registers.
The USB frame and transaction related interrupt events, such as Start of Frame interrupt, are
grouped in one set of registers: USB Interrupt Flag Register, USB Interrupt Enable Register
and USB Interrupt Mask Register. The USB Bus reset and suspend/resume are grouped in
another set of registers: Suspend/Resume Register, Suspend/Resume Interrupt Enable Reg-
ister and Suspend/Resume Interrupt Mask Register.
Some applications may include firmware routines lasting for long periods of time that cannot
be interrupted. At the same time, other less critical events may need attention after the critical
routine is completed. The AT43USB355 solves this problem by having interrupt mask registers
in addition to the interrupt enable registers of the USB related interrupts. The difference
between the mask and the enable registers is:
•
•
Address
$000
$004
$00E
$018
;
$00d
start
$00e
$00f
$010
$011
...
The enable register enables the interrupt so it is captured into the interrupt register. If it is
not enabled and an interrupt occurs, the interrupt will be lost,
The mask register merely masks the interrupt from interrupting the CPU. Upon
unmasking, the pending interrupt is triggered.
Labels
MAIN:
...
...
Code
jmp
jmp
jmp
jmp
ldi r16, high (RAMEND)
out SPH, r16
ldi r16, low (RAMEND)
out SPL, r16
<instr> xxx
...
RESET
EXT_INT1
TIM0_OVF
USB_HW
AT43USB355
Comments
; Reset Handler
; IRQ1 Handler
; Timer0 Overflow
; USB Handler
; Main Program
Handler
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