timer_isr.asm

胎压检测系统接收部分源码

* Timer_ISR.asm

**************************************************************
* Timer overflow interrupt service routine.                  *
* The timer will overflow if there is a long (1ms) delay     *
* between received bits on the SPI.  This is here because    *
* sometimes the Romeo will quit sending data in the middle   *
* of the data frame...                                       *
**************************************************************
Timer_ISR:      LDA     TSC
                MOV     #%01110000,TSC                  ;Get the timer ready, stop the counter.
                PULA                                    ;Trash the CCR value stored in the stack
                PULA                                    ;Trash the AR value stored in the stack
                PULA                                    ;Trash the XR value stored in the stack
                PULA                                    ;Trash the PCH value stored in the stack
                PULA                                    ;Trash the PCL value stored in the stack
                CLI                                     ;Clear the interrupt bit (enable int)
                BSET    2,TBCR                          ;Unmask TBM interrupts.

                JMP     GetSpiData

                ;There is no RTI instruction here; its operation is not needed.