Toshiba TC9349AFG Manual

TC9349AFG2006-02-2437(2) Detected power supply OFF functionDetected power supply OFF function detects the fact that the power supply is off during battery exchange or similarprocedures and actuates the backup state of the CPU circuit (VCPU pin) to keep it on hold.If the detected power supply off function is enabled (BRAEK ENA bit (φL11(F)) = "1"), the V DD pin level is about0.5 V or less and all functions stop. At this time, the V CPU pin power supply changes to low current consumption (0.5μA or less); the LCD output pin and CMOS output port change to “L” level; the N-channel open-drain pins are allautomatically fixed to the off (high-impedance) state; and the PLL changes to off mode. If the power supply isswitched on again, the CPU will operate after a standby interval of 100 ms. The VDD OFF F/F bit enables detection ofwhether the power supply has been switched off.Note: Set the V DD pin level to GND level during power supply off. If V DD level potential remains, currentwill be consumed by the V CPU pin.Note: The BRAEK ENA bit (φL11(F)) permits VDD power supply break and power supply off detectionfunction.Note: Use this function together with the decreased voltage detection function.(3) Backup control register by hardwareDecreased voltage detection and power supply off detection function control are accomplished through access of thedecreased voltage control port (φL11(E), φL11(F)); the decreased voltage detection setting data port (φL16(D),φK11(D)); and the flag register (φK26).φL11(E) (decreased voltage control 1)Note: If the decreased voltage detection function is not being used, set the WAIT ENA bit to "0" forreduced consumption current.Y1 Y2 Y4 Y8WAITENAPLLoffENASTOPENA *0: Prohibition Decreased voltage detection function suspended1: Enable Decreased voltage detection function operatingPermission for decreased voltage detection function0: Prohibition1: Enable PLL off mode and PLL stop are executedwhen decreased voltage is detected.Permission for PLL stop function on decreased voltage detection0: Prohibition1: Enable CPU stops when decreased voltage is detected.Permission for CPU stop function on decreased voltage detection(Note) Settings become invalid if the decreased voltagedetection function is suspended.