SLAS191A Datasheet, PDF (77/86 Pages) Texas Instruments – Starter Kit Evaluation Kit Manual

6 Using Interrupt Vectors in the EPROM
This chapter describes how to use interrupt vectors stored in the EPROM. The interrupt vectors are stored
in EPROM so they are not lost when power is removed.
6.1 The Identification Bit Pattern After a Reset
The reset start-up sequence checks the contents of memory location E9DEh to see if its contents are equal
to AA55h. If the memory location contents equal AA55h, the EPROM interrupt vector table with addresses
ranging from E9E0h to E9FEh is copied to the interrupt table in the RAM locations 3E0h to 3FEh on the
MSP430x32x, or 5E0h to 5FEh on the MSP430x33x family, and the key for the software UART is set to
AA55h to switch the monitor off. If the contents of memory location E9DEh are equal to 0000h, the next set
of interrupt vectors, located at 22h below the previous location, is tested like the first set previously
described. If the valid identification is set to AA55h after each power up or hardware reset, the user program
starts and the EPROM monitor is switched off. The only way back to the monitor is an indirect branch to
Ret_Mon (0FFDCh). The user program code implements a branch, as well as the condition for the branch.
6–1