Datasheet

Interrupts
7−1
SLLS535E − April 2008 TUSB6250
7 Interrupts
7.1 8051 Interrupt and Status Registers
Most 8051 standard interrupt sources (except external interrupt-0 and external interrupt-1) are supported. In
addition, interrupt-5 and interrupt-6 are provided. The real-time kernel (RTK) uses interrupt-6. All additional
internal interrupt sources specified in Section 7.2, Additional Interrupt Sources, are ORed together to generate
interrupt-5. The standard interrupt enable (IE) register controls the enabling of the interrupt source.
External interrupt-0 and external interrupt-1 are not implemented (wired) in the TUSB6250.
There are some minor differences in the vector address between the standard 8051 and the TUSB6250. The
standard 8051 has all the interrupt vector addresses starting with the prefix of 0x0000. In the TUSB6250, all
interrupts being serviced perform a long jump from the boot code to 0x2xxx locations listed in Table 7−1. The
EI5 has an additional overhead of eight instruction cycles before the boot code can jump to location 0x202B.
The firmware must implement a vector address table starting at 0x2000 instead of 0x0000.
Unless specified, all standard 8051 interrupt registers listed in this section can be cleared by either a power-up
reset or a WDT reset. They can also be cleared by a USB reset, when the function reset connection bit in the
USBCTL register is set (FRSTE = 1).
Table 7−1. 8051 Standard/Extended Interrupt Location Map for Application Firmware
INTERRUPT
SOURCE
DESCRIPTION
VECTOR ADDRESS
FOR FIRMWARE
COMMENTS
EI6 RTK interrupt 0x2033 Interrupt for RTK support
EI5 Internal interrupt-5 (INT5) 0x202B Used for internal vector interrupts
ES UART interrupt 0x2023
ET1 Timer-1 interrupt 0x201B
EX1 External interrupt-1 (INT1) 0x2013 Not implemented
ET0 Timer-0 interrupt 0x200B
EX0 External interrupt-0 (INT0) 0x2003 Not implemented
Reset 0x2000
After a power-up or a WDT reset, the boot code jumps
to 0x2000, once the firmware download is finished.
NOTE: The interrupt and register bits marked in the shaded areas of this table are not implemented in the TUSB6250.