In SX Microcontrollers, SX/B Compiler and SX-Key Tool, g_daubach wrote:

Hi electronic,

jumping to any location outside of the ISR, like to the top of program memory would mess up the shadow registers, as the RETI, or RETIW instruction is not executed. The same is true for the return stack when you try to jump to some address outside of a subroutine without executing a RET, RETW, or RETP instruction.

I have tried SXSim together with a jump to the top of program memory from within an ISR. SXSim stays in an endless loop, always jumping to the top of program memory. I'm not sure if the "real silicon" behaves the same but at least, SXSim does not simply ignore this "illegal" code.

BTW: You can also soft-reset the SX w/o using the watchdog by connecting a free port pin to the *MCLR pin. Configure this port pin as an input (high Z) by default. In case you want to soft-reset the SX, make this pin an output with low level. This will pull low the *MCLR pin, and cause a reset. As a reset automatically configures all port pins as inputs (high Z), *MCLR will be released automatically after the soft-reset.

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