ST2202A
22. LOW VOLTAGE DETECTOR
ST2202ꢀhasꢀaꢀbuiltꢁinꢀlowꢀvoltageꢀdetectorꢀforꢀpowerꢀ
management.ꢀTheꢀtypicalꢀactiveꢀlevelꢀofꢀvoltageꢀdetectionꢀisꢀ
2.6V.ꢀWhenꢀLVDENꢀ(SYS[0])ꢀisꢀset,ꢀdetectorꢀcircuitꢀisꢀ
enabledꢀandꢀtheꢀdetectionꢀresultꢀwillꢀbeꢀoutputtedꢀatꢀtheꢀ
sameꢀbitꢀafterꢀ3ꢀꢀs.ꢀUsingꢀreadꢀinstructionꢀtwiceꢀcanꢀgetꢀthisꢀ
result:ꢀfirstꢀreadꢀwillꢀenableꢀinitialꢀstablenessꢀcontrol.ꢀ
Secondꢀreadꢀequalꢀ'0'ꢀrepresentsꢀ'lowꢀvoltage'.ꢀOnceꢀlowꢀ
voltageꢀdetectorꢀisꢀenabled,ꢀitꢀkeepsꢀonꢀconsumingꢀpower.ꢀ
Soꢀitꢀisꢀimportantꢀthatꢀrememberꢀtoꢀwriteꢀ“0”ꢀtoꢀLVDETꢀtoꢀ
disableꢀtheꢀdetectorꢀafterꢀdetectionꢀisꢀcompleted.ꢀOneꢀ
sampleꢀprogramꢀisꢀshownꢀbelow:ꢀ
Start:
SMB0ꢀ <SYSꢀ
:ꢀ
;ꢀenableꢀdetectorꢀ
Wait 3 ꢀs
:ꢀ
SECꢀ
BBS0ꢀ <SYS,$+3ꢀ
BBS0ꢀ <SYS,Normal_Voltage
Low_Voltage:ꢀ
ꢀ
CLCꢀ
Normal_Voltage:
RMB0ꢀ <SYSꢀ
;ꢀdisableꢀdetectorꢀ
ꢀ
ꢀ
Verꢀ2.5ꢀ
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9/16/2008ꢀ
SITRONIX [ SITRONIX TECHNOLOGY CO., LTD. ]
