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Power Feature ACEx Microcontrollers Fairchild Note 8012 Kevin Han
Top Searches for this datasheetAN-8012 Power Feature ACEx Microcontrollers Fairchild Note 8012 Kevin Hansen August 2000 ACEx family microcontrollers have power saving feature called HALT mode that allows very power consumption. While microcontroller HALT, device's main circuits powered-down. possible 5-10 years battery life from small lithium battery when HALT used application such wireless remote control. application such this, microcontroller will HALT mode most time waiting button push wake device start transmitting data. HALT mode, current drain less that 1µA. This document describes HALT mode feature ACEx family microcontrollers. This routine starts configuring I/O's calling subroutine HALT1. HALT1 routine sets wakeup device negative edge then clears pending register places device HALT mode. device will stay HALT mode until high transition. When high wakeup signal sensed part comes HALT resets Power Mode Clear (PMC) Register 0x00. Clearing Register should always first instruction upon exiting HALT mode. this time delay added wait switch bouncing end. more than enabled wake device from HALT mode, software read WKPND register determine which caused wakeup. return from HALT1 subroutine outputs HALT1 subroutine re-called second time. This time, upon returning from HALT1 subroutine, outputs high. routine then jumps back repeat process over again. Simple HALT mode Example example HALT mode found HALT Example below. This routine sets outputs high then places device into HALT. When high signal transition sensed pin, device comes HALT toggles outputs low. Each time high signal transition sensed device comes HALT mode, toggles outputs, goes back into HALT mode. state I/O's change while HALT mode. 1101 Outputs Figure microcontroller will normally power HALT mode. When pressed, comes HALT mode, toggles outputs, goes back into HALT mode. AN-8012 Rev. www.fairchildsemi.com AN-8012 HALT Example .DEVICE ACE1101 PORTGC, #11100111B ;all output weak pullup input PORTGD, #11111111B ;all output high TOP: HALT1 PORTGD, #00011000B ;all outputs HALT2: HALT1 PORTGD, #11111111B ;all output high HALT1: WKEN SBIT WKEN ;SET WAKEUP SBIT WKEDG ;SET WAKEUP EDGE WKPND ;CLEAR PENDING REGISTER HALT, #01H INTO HALT MODE PMC, #00H ;Clear Power Mode Register delay switch debounce added here needed Life Support Policy Fairchild's products authorized critical components life support devices systems without express written approval President Fairchild Semiconductor Corporation. used herein: Life support devices systems devices systems which, intended surgical implant into body, support sustain life, whose failure perform, when properly used accordance with instructions provided labeling, reasonably expected result significant injury user. Fairchild Semiconductor Americas Customer Response Center Tel. 1-888-522-5372 Fairchild Semiconductor Europe Fax: 1793-856858 Deutsch Tel: 8141-6102-0 English Tel: 1793-856856 Tel: 1-6930-3696 Italiano Tel: 2-249111-1 critical component component life support device system whose failure perform reasonably expected cause failure life support device system, affect safety effectiveness. Fairchild Semiconductor Hong Kong 8/F, Room 808, Empire Centre Mody Road, Tsimshatsui East Kowloon. Hong Kong Tel; +852-2722-8338 Fax: +852-2722-8383 Fairchild Semiconductor Japan Ltd. Natsume Bldg. 2-18-6, Yushima, Bunkyo-ku Tokyo, 113-0034 Japan Tel: 81-3-3818-8840 Fax: 81-3-3818-8841 Fairchild does assume responsibility circuitry described, circuit patent licenses implied Fairchild reserves right time without notice change said circuitry specifications. AN-8012 Rev. www.fairchildsemi.com Other recent searchesIS32WV16100A - IS32WV16100A IS32WV16100A Datasheet IS32WV16200A - IS32WV16200A IS32WV16200A Datasheet HSM126S - HSM126S HSM126S Datasheet DS2401 - DS2401 DS2401 Datasheet CD110G - CD110G CD110G Datasheet BA282 - BA282 BA282 Datasheet BA283 - BA283 BA283 Datasheet 2N5551- - 2N5551- 2N5551- Datasheet
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