Motorola MVME162 Memory Requirements, SYSFAIL* Assertion/Negation, MPU Clock Speed Calculation

Debugger General Information

Many times it may be desirable to terminate a debugger command prior to its completion; for example, during the display of a large block of memory. Break allows you to terminate the command.

3SYSFAIL* Assertion/Negation

Upon a reset/powerup condition the debugger asserts the VMEbus SYSFAIL* line (refer to the VMEbus specification). SYSFAIL* stays asserted if any of the following has occurred:

❏confidence test failure

❏NVRAM checksum error

❏NVRAM low battery condition

❏local memory configuration status

❏self test (if system mode) has completed with error

❏MPU clock speed calculation failure

After debugger initialization is done and none of the above situations have occurred, the SYSFAIL* line is negated. This indicates to the user or VMEbus masters the state of the debugger. In a multi-computer configuration, other VMEbus masters could view the pertinent control and status registers to determine which CPU is asserting SYSFAIL*. SYSFAIL* assertion/negation is also affected by the ENV command. Refer to Appendix A.

MPU Clock Speed Calculation

The clock speed of the microprocessor is calculated and checked against a user definable parameter housed in NVRAM (refer to the CNFG command in Appendix A). If the check fails, a warning message is displayed. The calculated clock speed is also checked against known clock speeds and tolerances.

Memory Requirements

The program portion of 162Bug is approximately 512KB of code, consisting of download, debugger, and diagnostic packages and contained entirely in Flash or PROM.

The 162Bug executes from $FF800000 whether in Flash or PROM. With jumper at J22 pins 9-10 installed (factory ship configuration), the Flash memories appear at address $FF800000 and are the parts executed during reset. With this configuration, the PROM socket is mapped to address $FFA00000. If you remove the jumper at J22 pins 9 and 10, the address spaces of the Flash and PROM are swapped.

3-10 MVME162 Embedded Controller Installation Guide