ZBasicRef - page 104 of 172

ZBasic Language Reference

ZX Microcontroller Family

Used by WaitForInterrupt().

Used by the RTC, cannot be replaced.

Used by OpenCom() for channels 3-6 (software UART).

Used by OpenX10() along with INT0.

Used by InputCapture().

Used by ComToDAC() and DACToCom1().

Used by OutputCapture().

Used by Com1, cannot be replaced.

Used by OpenCom() for channels 2 (and 7 or 8 where supported).

For the ZX-1281e and ZX-1281ne, the roles of USART0 and USART1 are reversed.

For the form of ISR definition shown in the example above, the compiler takes care of saving the

necessary registers upon entry, establishing the standard register state, restoring registers upon exit and

executing a “return from interrupt” instruction. For special cases, you may define a “naked” ISR – one in

which none of this is done. Using this special form is advised only for advanced programmers,

particularly those that understand the nuances of the underlying code.

An example of a naked ISR containing only a “return from interrupt” is shown below. This is commonly

called a “stub” ISR. It is important to note that defining a naked ISR with no code statements in it at all