Nesting Interrupt (irq) Functions on MCB2100 with CARM

This examples shows nesting of classic interrupt (irq) functions on the MCB2100 Board. It uses two interrupts Timer0 (tc0) and external interrupt (EINT1 input assigned to GPIO 0.14 and connected to INT1 push button on Keil MCB2100 when jumper INT1 is ON).

The interrupt pin is configured edge sensitive. Whenever you release the push button a counter is incremented that is output to the LED's connected to GPIO 1.16 - 1.22. Inside the EINT function, there is a long delay function that is just implemented to waste CPU time.

The timer interrupt is called every 100uSec and increments every second the variable SecondCnt. GPIO 1.23 outputs an one second pulse that is derived from this timer interrupt.

The project is available configured for two targets:

• Simulator: runs without hardware on uVision Simulator
• MCB2100: runs on Keil MCB2100 (with ULINK as debugger/programmer)

Under Simulation you may use the Logic Analyzer to review the operation of the program. A debug function generates 100ms interrupt pulses at debugger startup.

You may manually generate interrupts by changing the state of GPIO 0.14 under Peripherals - GPIO - Port 0

A simulator script provides a signal function that generates input pulses on GPIO PORT0.14. This signal function may be triggered from buttons in the Toolbox (opens with View - Toolbox).