e. Interrupt Flags
i. Edge vs. level
a. Clearing a flag
Interrupts may be globally disabled by setting the flag to one.
On reset the flag is set.
Clear the flag to enable interrupts.
Edge | level |
1. A high to low signal triggers the interrupt | 1.default made upon reset of the 8051 |
2.Need to set TCON.0(IT0)/TCON.2(IT1) | 2.A low-level signal triggers the interrupt. |
3.TCON.1(IE0) AND TCON.3(IE1) are set when an falling edge is detected and cleared by RETI | 3.The low signal must be held low before the execution of ISR and must be removed before RETI |
Clearing a flag:
In microproccessor causing a flag to become 0 is clearing a flag
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