Appendix C: Mask Option Register MTT48 V2.0 C - 3 An EPROM/OTPROM byte that enables or disables the following options: –Operation of low-voltage inhibit module (LVI) during stop mode –Resets caused by the LVI module –Power to the LVI module –Stop mode ecovery time (32 CGMXCLK cycles or 4096 CGMXCLK cycles) –EPROM/OTPROM security (1) –STOP instruction –Computer operating properly (COP) Mask Option Register
Appendix C: Mask Option Register MTT48 V2.0 C - 4 RESET: UNAFFECTED BY RESET WRITE: MOR READ: 0 LVISTOP LVIRST LVIPWR SSREC SEC STOP COPD LVI Enable in Stop Mode (LVISTOP) –If LVIPWR bit is at logic one, LVISTOP enables the LVI modules to operate during stop mode –1 = LVI not disabled by STOP instruction –0 = LVI disabled by STOP instruction LVI Reset (LVIRST) –Enables reset when LVIOUT is set –MPU remains in reset until V DD rises above LVI TRIP –Allow LVI SETTLE time before enabling 1 = LVI reset enabled 0 = LVI reset disabled LVI Power Enable (LVIPWR) –Applies power to the LVI analog circuitry –Disabling will stop current drain form the LVI –1 = Power applied –0 = Power not applied Mask Option Register
Appendix C: Mask Option Register MTT48 V2.0 C - 5 RESET: UNAFFECTED BY RESET WRITE: MOR READ: 0 LVISTOP LVIRST LVIPWR SSREC SEC STOP COPD Short Stop Recovery (SSREC) –EnablesCPU to exit stop mode with a short or long delay –1 = Stop Mode recovery after 32 CGMXCLK cycles –0 = Stop Mode recovery after 4096 CGMXCLK cycles EPROM/OTPROM Security (SEC) –Enables EPROM/OTPROM security feature –Setting SEC prevents reading EPROM/OTPROM Contents –1 = EPROM/OTPROM Security enabled –0 = EPROM/OTPROM Security disabled STOP Enable (STOP) –Enables the STOP instruction –1 = STOP instruction enabled –0 = STOP instruction treated as illegal opcode COP Disable (COPD) –Disables COP Module –1 = COP module disabled –0 = COP mdoule enabled Mask Option Register
Appendix C: Mask Option Register MTT48 V2.0 C - 6 Mask Option Register Programming Sequence Sequence for programming Mask Option Register: 1) Apply V DD + V HI to the IRQ1/V PP pin 2) Set the ELAT bit in the EPROM control register 3) Write to the mask option register Note: writing to an invalid address prevents the programming voltage from being applied. 4) Set the EPGM bit 5) Wait for a time, t EPGM. 6) Clear the ELAT and EPGM bits note: –Setting the ELAT and EPGM bit with one instruction will set ELAT but clear EPGM. –EPGM must be set by a separate instruction in the programming sequemce.