Mostek z80 - Execution Timer Operation; Operation with MD-SBC1; Operation with MDX

3-51
3.76 EXECUTION TIMER OPERATION
The execution timer is implemented as a sixteen bit hardware counter which
counts Target clock periods. The execution timer is extended to thirty-two
bi ts with software and is automatically enabled durin:] execution. The
execution time is automatically printed when a breakpoint is encountered or
when single stepping. The execution time is reset any time execution is
started at a particular address. The time is not reset when execution is
continued. If the user desires the time to be displayed in microseconds,
the Target clock period (:TS) must be initialized (see examples in section
3.1S) • The AH1Z80A program defaults to 10100nS (1.0 MHz) unless the
user changes it. For 1000nS, the number of microseconds is coincidentally
the same as the number of T-states.
The execution timer may also be used to cause execution to terminate after a
specified number of Target clock periods or Time (Timer breakpoint). 'fb set
a timer breakpoint see section 3.1S.
3.77 OPERATION WITH l~SBCl
AIM-Z80AE can be used with the Mostek MD-SBCl single board computer with no
modifications or jumbers required. If the Emulation RAl"I is used, the PRavI
on the MD-SBCl must be disabled or removed for the address space emulated.
3.78 OPERATION WITH MDX
AIM-ZS0AE can also be used with the Mostek MDX-CPUI in a system wi th no
jumpers or modifications required. If the Emulation RAM is used, the PRavI
(U7) should be removed and the chip enable for U7 (US pin S) should be
enabled for all memory space emulated. AIM-ZS0AE can also be used with the
Mostek MDX-CPU2. If Emulation RAM is used to emulate PROM, the PROM must be
removed and the PRCM chip enable active for the emulated memory space to
prevent Bus conflict.