COMPAL-A-LA-1961_DAT20

1、 ABCDEA-PDF Watermark DEMO: Purchase from www.A-PDF.com to remove the watermark12341234Compal ConfidentialDAT20 Schematics DocumentBanias uFCPGA Package with 855PM(Odem) + ICH4-M2003-10-23REV: 1.0Compal Electronics, Inc.TitleCover SheetTHIS SHEET OF ENGINEERING DRAWING IS THE PROPRIETARY PROPERTY OF

2、 COMPAL ELECTRONICS, INC. AND CONTAISNiSzeCONFDIDoEcuNmTeIAnLt NumberRev1.0AND TRADE SECRET INFORMATION. THIS SHEET MAY NOT BE TRANSFERED FROM THE CUSTODY OF THE COMPETENT DIVCIuSsIOtoNm OFDRA&TD20 LA-1971DEPARTMENT EXCEPT AS AUTHORIZED BY COMPAL ELECTRONICS, INC. NEITHER THIS SHEET NOR THE INFORMAT

3、ION IT CONTAINSMAY BE USED BY OR DISCLOSED TO ANY THIRD PARTY WITHOUT PRIOR WRITTEN CONSENT OF COMPAL ELECTRONICSD, aI Nt eC: .Tuesday, November 11, 2003SheetE1of42ABCD ABCDECompal confidentialBlock DiagramModel Name : DAT20File Name : LA-1971 Rev:1.0Part Number : DA8AT20L010Mobile BaniasuFCPGA CPUT

4、hermal SensorADM1032ARMClock GeneratorICS950810CG478pinpage 4,5page 4page 1211234Fan ControlCRTTV-OUT CONN.HA#(3.31)System BusHD#(0.63)page 29400MHzpage 18MemoryBUS(DDR)Odem-BDDR-SO-DIMM X2BANK 0, 1, 2, 3VGABoardAGP4X(1.5V)2.5V 200/266/333MHzpage 9,10,11AGP ConnuFCBGA-593 pinpage 17PIRQA#page 6,7,8H

5、UB-LINKIDSEL: AD20PIRQA#GNT#2, REQ#2SERIRQIDSEL: AD18USB port 4USB port 5USB port 0, 2USBx2PIRQG#, PIRQH#GNT#1, REQ#1GNT#4, REQ#4IDSEL: AD16PIRQE#GNT#0, REQ#0IDSEL: AD17PIRQF#GNT#3, REQ#3I-StickPCI BUSBlueTooth I/F3.3V 33MHz3.3V 48MHzUSB connICH4-Mpage 24page 26page 24MINIPCI I/F1394 ControllerLANCa

6、rdBusENE CB1410BGA-4213.3V 24.576MHz3.3V ATA100AC-LINKTI TSB43AB21ARTL 8101Lpage 13,14,15page 23page 22page 21page 191394Connector3RJ45page 21Slot 0LPC BUS3.3V 33MHzpage 20page 22DC/DC InterfaceSuspendLED INDICATORSIO LPC47N217TPMMS/SD/MMCW83L518DENE KB910AC97HDDCDROMCodecSLD9630TTBas I/O Address 4E

7、hpageLPC to X-BUS& KBCpage 33page 17page 29Base I/O Address 2Ehpage 25page 16page 16ALC250Base I/O Addspage 30p epagePower CircuitDC/DCPower On/OffReset & RTCPARALLELAMP& PhoneJackpagepage 26BIOSTouch Pad34,35,36,37,38,39,40page 29page 28page 17page 314FIRInt.KBDpage 24page 17Compal Electronics, Inc

8、.Block DiagramLegacy I/O OptionTitleTHIS SHEET OF ENGINEERING DRAWING IS THE PROPRIETARY PROPERTY OF COMPAL ELECTRONICS, INC. AND CONTAISNiSzeCONFDIDoEcuNmTeIAnLt NumberRev1.0AND TRADE SECRET INFORMATION. THIS SHEET MAY NOT BE TRANSFERED FROM THE CUSTODY OF THE COMPETENT DIVCIuSsIOtoNm OFDRA&TD20 LA

9、-1971DEPARTMENT EXCEPT AS AUTHORIZED BY COMPAL ELECTRONICS, INC. NEITHER THIS SHEET NOR THE INFORMATION IT CONTAINSMAY BE USED BY OR DISCLOSED TO ANY THIRD PARTY WITHOUT PRIOR WRITTEN CONSENT OF COMPAL ELECTRONICSD, aI Nt eC: .Tuesday, October 28, 2003SheetE2of42ABCD 笔记本图A纸大全 QQ 107B203753CDEH_RS#0.

10、2D# 0. 63H_RS# .26#6+3VSHA#3.316HA#3.31H_REQ#0.46H_REQ#0.4JP11AA3#A4#A5#A6#A7#A8#A9#12HA#3HA#4HA#5HA#6HA#7HA#8HA#9P4U4V3R3V2W1T4W2Y4Y1U1AA3Y3AA2AF4AC4AC7AC3AD3AE4AD2AB4AC6AD5AE2AD6AF3AE1AF1BaniasA19A25A22B21A24B26A21B20C20B24D24E24C26B23E23C25H23G25L23M26H24F25G24J23M23J25HD#0HD#1HD#2HD#3HD#4HD#5HD#

11、6HD#7C50D0#D1#D2#D3#D4#D5#D6#D7#D8#Place closed toCPU related PinA18 / B180.1U_0402_16V4ZR2710K_0402_5%12C492200P_0402_50V7KU912341THERMDATHERMDC23871+VCCPHA#10HA#11HA#12HA#13HA#14HA#15HA#16HA#17HA#18HA#19HA#20HA#21HA#22HA#23HA#24HA#25HA#26HA#27HA#28HA#29HA#30HA#31D+VDD1ALERT#A10#A11#A12#A13#A14#A15

12、#A16#A17#A18#A19#A20#A21#A22#A23#A24#A25#A26#A27#A28#A29#A30#A31#HD#8HD#9645D-D9#11R2216150_0402_5%ITP_TDIHD#10HD#11HD#12HD#13HD#14HD#15HD#16HD#17HD#18HD#19HD#20HD#21HD#22HD#23HD#24HD#25HD#26HD#27HD#28HD#29HD#30HD#31HD#32HD#33HD#34HD#35HD#36HD#37HD#38HD#39HD#40HD#41HD#42HD#43HD#44HD#45HD#46HD#47HD#4

13、8HD#49HD#50HD#51HD#52HD#53HD#54HD#55HD#56HD#57HD#58HD#59HD#60HD#61HD#62HD#631032_THERM#D10#D11#D12#D13#D14#D15#D16#D17#D18#D19#D20#D21#D22#D23#D24#D25#D26#D27#D28#D29#D30#D31#D32#D33#D34#D35#D36#D37#D38#D39#D40#D41#D42#D43#D44#D45#D46#D47#D48#D49#D50#D51#D52#D53#D54#D55#D56#D57#D58#D59#D60#D61#D62#D

14、63#27 EC_SMC227 EC_SMD2SCLKSDATATHERM#GNDR2214680_0402_5%ITP_TRST#ADM1032ARM_RM8Note:Placement near to CPU ConnADDR GROUPDATA GROUPL26N24M25H26N25K25Y26AA24T25H_REQ#0H_REQ#1H_REQ#2H_REQ#3H_REQ#4R2P3T2P1T1REQ0#REQ1#REQ2#REQ3#REQ4#U23V23U3AE566H_ADSTB#0H_ADSTB#1ADSTB0#ADSTB1#R24R26R23AA23U26V24U25V26Y

15、23AA26Y25AB25AC23AB24AC20AC22AC25AD23AE22AF23AD24AF20AE21AD21AF25AF22AF26A16A1512 CLK_CPU_ITP12 CLK_CPU_ITP#ITP_CLK0ITP_CLK1B15B1412 CLK_CPU_BCLK12 CLK_CPU_BCLK#BCLK0BCLK1HOST CLK+VCCPN2L1J3N4L4H2K3K4A4J266H_ADS#H_BNR#ADS#BNR#BPRI#BR0#DEFER#DRDY#HIT#HITM#IERR#LOCK#RESET#12ITP_TDO6H_BPRI#H_BR0#R21715

16、4.9_0402_1%H_CPURST#54.9_0402_1%ITP_TMS39.2_0603_1%626H_DEFER#R2191666H_DRDY#H_HIT#H_HITM#2CONTROL GROUPR22012H_IERR#+VCCPR22812ITP_TCK27.4_0402_1%6H_LOCK#H_CPURST#56_0402_5%H_CPURST# B11R2156H_RS#0H_RS#1H_RS#2H1K1L2RS0#RS1#RS2#TRDY#Note:Placement near to ITP Conn3M36H_TRDY#D25J26T24Place closed to

17、CPU pin B17DINV0#DINV1#DINV2#DINV3#H_DINV#06666H_DINV#1H_DINV#2H_DINV#3T1T2T3T4PAD BPM0# C8PAD BPM1# B8PAD BPM2# A9PAD BPM3# C9BPM0#BPM1#BPM2#BPM3#R224150_0402_5%1AD2012H_PROCHOT#56_0402_5%+VCCPR2092R2230_0402_5%+3VALW14 ITP_DBRESET#C23K24W25AE24C22L24DSTBN0#DSTBN1#DSTBN2#DSTBN3#DSTBP0#DSTBP1#DSTBP2

18、#H_DSTBN#0H_DSTBN#1H_DSTBN#2H_DSTBN#3H_DSTBP#0H_DSTBP#1H_DSTBP#2H_DSTBP#366666666ITP_DBRESET#12A7M2B7C19A10B10DBR#6H_DBSY#7,13 H_DPSLP#H_DPWR#2R227330_0402_5%DBSY#DPSLP#DPWR#PRDY#PREQ#71MISCW24AE25+VCCPH_PROCHOT#B17PROCHOT#DBP3#E4A6A13C12A12C513 H_PWRGDPWRGOODSLP#TCKTDITDOTEST1TEST2TMS13 H_CPUSLP#R2

19、26ITP_TCKITP_TDIITP_TDOTEST1TEST2ITP_TMS1K_0402_5%C2D3A3B5D1D4A20M#FERR#IGNNE#INIT#H_A20M# 131122H_FERR# 13H_IGNNE# 13H_INIT# 13H_INTR 13H_NMI 13F23C11R2081K_0402_5%ITP_TRST# B13TRST#LINT0LEGACY CPULINT14THERMALC6B4STPCLK#SMI#H_STPCLK# 13H_SMI# 13THERMDA B18THERMDC A18THERMDA DIODETHERMDCC1714 H_THE

20、RMTRIP#THERMTRIP#Compal Electronics, Inc.Banias Processor in mFCPGA479 (1/2)AMP_1473129-1TitleTHIS SHEET OF ENGINEERING DRAWING IS THE PROPRIETARY PROPERTY OF COMPAL ELECTRONICS, INC. AND CONTAISNiSzeCONFDIDoEcuNmTeIAnLt NumberRev1.0AND TRADE SECRET INFORMATION. THIS SHEET MAY NOT BE TRANSFERED FROM

21、 THE CUSTODY OF THE COMPETENT DIVCIuSsIOtoNm OFDRA&TD20 LA-1971DEPARTMENT EXCEPT AS AUTHORIZED BY COMPAL ELECTRONICS, INC. NEITHER THIS SHEET NOR THE INFORMATION IT CONTAINSMAY BE USED BY OR DISCLOSED TO ANY THIRD PARTY WITHOUT PRIOR WRITTEN CONSENT OF COMPAL ELECTRONICSD, aI Nt eC: .Monday, October

22、 27, 2003Sheet4of42ABCDE ABCDE+CPU_CORE1+CPU_COREJP11CVCC111F20F22T26U2VSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSV

23、SSVSSVSSVSSVSSVSSVSSVSSVSSJP11B+C341+C347+C357+C363VCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCG5G21H6H22J5J21K22U5V6V22W5W21Y6Y22AA5AA7AA9AA11AA13AA15AA17AA19AA21AB6U6U22U2

24、4V1V4V5V21V25W3W6W22W23W26Y2Y5Y21Y24AA1R222R225112254.9_0402_1%54.9_0402_1%VCCSENSEVSSSENSEAE7AF6A2A5A8A11A14A17A20A23A26B3VCCSENSEVSSSENSEVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSS2222220U_D2_4VM_R12220U_D2_4VM_R12220U_D2_4VM_R12220U_D2_4VM_R12F26B1N1+1.8VS+VCCPVCCA0VCCA1

25、VCCA2VCCA31234+CPU_COREAC26P23W41121212121212VCCQ0VCCQ1B6B9C340C339C338C337C336C335C334BaniasBaniasB12B16B19B22B25C1C4C7C10C13C152D10D12D14D16E11E13E15F10F12F14F16K6L5L21M6M22N5N21P6VCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCPVCCP10U_0805_6.3V6M10U

26、_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M+CPU_COREAA4AA6AA811112121212AA10AA12AA14AA16AA18AA20AA22AA25AB3C333C344C349C353C359C365C366POWER, GROUNG, CR1E8 SERVED SIGNALS AND NCAB8VSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSV

27、SSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSS222C21C24D2D5D7AB10AB12AB14AB16AB18AB20AB22AC9AC11AC13AC15AC17AC19AD8AD10AD12AD14AD16AD18AE9AE11AE13AE15AE17AE19AF8AF10AF12AF14AF16AF1810U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6

28、.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6MPOWER, GROUND+CPU_CORED9AB5AB7AB9D11D13D15D17D19D21D23D26E311112121212P22R5R21T6T22U21AB11AB13AB15AB17AB19AB21AB23AB26AC2AC5AC8AC10AC12AC14AC16AC18AC21AC24AD1AD4AD7AD9AD11AD13AD15AD17AD19AD22AD25AE3C367C368C369C370C371C364C36022210U_0805_6.3V6M10U_08

29、05_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M+CPU_COREE6E8D6D8D18D20D22E5E7E9E17E19E21F6+CPU_COREVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCVCCE10E12E14E16E18E20E22E25F1F4F5F7F9F11F13F15F17F19F21F24G211112121212C354C350C345C332C342C343C34822210U_0805_6.3V6M10U_0805

30、_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M+CPU_COREF8F1811112121212C352C358C362C372C331C374C37340 PSI#E1PSI#222+VCCPE2F2F3G3G4H410U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6M40 CPU_VID040 CPU_VID140 CPU_VID240 CPU_VID340 CPU_VID440 CPU_VID5VID0VI

31、D1VID2VID3VID4VID510U_0805_6.3V6M10U_0805_6.3V6M10U_0805_6.3V6MM4M5M21M24N3VSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSVSSR261K_0402_1%G6AE6AE8G22G23G26H3Vcc-coreDecouplingSPCAP,Polymer 4X220uFC,uFESR, mohmESL,nHAE10AE12AE14AE16AE18AE20AE23AE26AF2(+0.7V)N612GTL_REF0AD26E26G112m oh

32、m/45m ohm/353.5nH/4N22N23N26P2GTLREF0RSVDRSVDR25Placed closed to Pin AD26within 0.5.H52K_0402_1%H21H25J1J4J6J22J24K2MLCC 0805 X5R 35X10uF0.6nH/35AC1RSVDP5+1.8VSP21P24R1R4R6R22R25T3T5T21T23RaRbRcRdR207R206R232R2312222111127.4_0402_1% COMP054.9_0402_1% COMP127.4_0402_1% COMP254.9_0402_1% COMP3P25P26AB

33、2AB1COMP0COMP1COMP2COMP3AF5AF912121212112121AF11AF13AF15AF17AF19AF21AF24K5K21K23K26L3622C48C324C378C379C47C319C380C381R230111122221K_0402_5%1K_0402_5%1K_0402_5%1K_0402_5%B2AF7C14C3RSVDRSVDRSVDRSVD212R221R212R2290.01U_0402_160.00.01U_0402_16V7K402_16V7K05K4Z10U_ 05_10V4Z_0805_10V 10U_0805_10V4Z0.01U_

34、0402_R210121K_0402_5%C1625M1TEST3AMP_1473129-1+VCCPAMP_1473129-11Ra, Rb, Rc, Rd placed close to related pin within 0.5.12111212112121212+COMP0/1/2/3 Trace should 25mil away from any other toggling signal.C382C375C376C3562C351C346C330C328C329C377C32742220.1U_0402_16V4Z150U_D2_6.3VM 0.1U_0402_16V4Z0.1

35、U_0402_16V4Z0.1U_0402_16V4Z0.1U_0402_16V4Z0.1U_0402_16V4Z0.1U_0402_16V4Z0.1U_0402_16V4Z0.1U_0402_16V4Z0.1U_0402_16V4ZCompal Electronics, Inc.Banias Processor in mFCPGA479 (2/2)TitleTHIS SHEET OF ENGINEERING DRAWING IS THE PROPRIETARY PROPERTY OF COMPAL ELECTRONICS, INC. AND CONTAISNiSzeCONFDIDoEcuNm

36、TeIAnLt NumberRev1.0AND TRADE SECRET INFORMATION. THIS SHEET MAY NOT BE TRANSFERED FROM THE CUSTODY OF THE COMPETENT DIVCIuSsIOtoNm OFDRA&TD20 LA-1971DEPARTMENT EXCEPT AS AUTHORIZED BY COMPAL ELECTRONICS, INC. NEITHER THIS SHEET NOR THE INFORMATION IT CONTAINSMAY BE USED BY OR DISCLOSED TO ANY THIRD

37、 PARTY WITHOUT PRIOR WRITTEN CONSENT OF COMPAL ELECTRONICSD, aI Nt eC: .Monday, October 27, 2003Sheet5of42ABCDE ABCDEH_RS#0.2HA#3.31H_REQ#0.44H_RS#0.2H0.6D#0.63HUB_PD0.104HA#3.31HUB_PD0:10 138BAGP_AD0.31AGP_C/BE#0.3AGP_SBA0.7Odem4H_REQ#0.417 AGP_AD0.31U8AAGP_AD0AGP_AD1AGP_AD2AGP_AD3AGP_AD4AGP_AD5AGP

38、_AD6AGP_AD7AGP_AD8AGP_AD9AGP_AD10AGP_AD11AGP_AD12AGP_AD13AGP_AD14AGP_AD15AGP_AD16AGP_AD17AGP_AD18AGP_AD19AGP_AD20AGP_AD21AGP_AD22AGP_AD23AGP_AD24AGP_AD25AGP_AD26AGP_AD27R27R28T25R25T26T27U27U28V26V27T23U23T24U24U25V24Y27P25P24N27P23M26M25L28L27M27N28M24HUB_PD0HUB_PD1HUB_PD2HUB_PD3HUB_PD4HUB_PD5HUB_P

39、D6HUB_PD7HUB_PD8HUB_PD9HUB_PD1017 AGP_C/BE#0.317 AGP_SBA0.7GAD0GAD1GAD2GAD3GAD4GAD5GAD6GAD7HI_0HI_1HI_2HI_3HI_4HI_5HI_6HI_7HI_8HI_9HI_10OdemHA#3HA#4HA#5HA#6HA#7HA#8HA#9U6T5R2U3R3P7T3P4P3P5R6N2N5N3J3M3M4M5L5K3J2AA2AB5AA5AB3AB4AC5AA3AA6AE3AB7AE5AF3AC6AC3AF4AE2AG4AG2AE7AE8AH2AC7AG3AD7AH7AE6HD#0HD#1HD#2

40、HD#3HD#4HD#5HD#6HD#7HA#3HA#4HA#5HA#6HA#7HA#8HA#9HD#0HD#1HD#2HD#3HD#4HD#5HD#6HD#7HD#812341234HUBGAD8GAD9GAD10GAD11GAD12GAD13GAD14GAD15GAD16GAD17GAD18GAD19GAD20GAD21GAD22GAD23GAD24GAD25GAD26GAD27GAD28GAD29GAD30GAD31HA#10HA#11HA#12HA#13HA#14HA#15HA#16HA#17HA#18HA#19HA#20HA#21HA#22HA#23HA#24HA#25HA#26HA

41、#27HA#28HA#29HA#30HA#31HA#10HA#11HA#12HA#13HA#14HA#15HA#16HA#17HA#18HA#19HA#20HA#21HA#22HA#23HA#24HA#25HA#26HA#27HA#28HA#29HA#30HA#31HD#8HD#9N25N24HI_STBHI_STB#HUB_PSTRB 13HUB_PSTRB# 13HD#9HD#10HD#11HD#12HD#13HD#14HD#15HD#16HD#17HD#18HD#19HD#20HD#21HD#22HD#23HD#24HD#25HD#26HD#27HD#28HD#29HD#30HD#31H

42、D#32HD#33HD#34HD#35HD#36HD#37HD#38HD#39HD#40HD#41HD#42HD#43HD#44HD#45HD#46HD#47HD#48HD#49HD#50HD#51HD#52HD#53HD#54HD#55HD#56HD#57HD#58HD#59HD#60HD#61HD#62HD#63HD#10HD#11HD#12HD#13HD#14HD#15HD#16HD#17HD#18HD#19HD#20HD#21HD#22HD#23HD#24HD#25HD#26HD#27HD#28HD#29HD#30HD#31HD#32HD#33HD#34HD#35HD#36HD#37H

43、D#38HD#39HD#40HD#41HD#42HD#43HD#44HD#45HD#46HD#47HD#48HD#49HD#50HD#51HD#52HD#53HD#54HD#55HD#56HD#57HD#58HD#59HD#60HD#61HD#62HD#63P27 HUB_RCOMPP2612R19836.5_0402_1%HLRCOMPHI_REF+1.8VSY26+HUB_VREFAA28AB25AB27AA27AB26Y23AB23AA24AA25AB2412C2910.01U_0402_16V7KAB9AD10AF9AJ9A7F8J7L8N8R8U8W8AA8AD8AF7AJ7D5F6H6K6M6P6T6V6Y6AB6AD6AF5AJ5A3J4L4N4R4U4W4AA4AC4AE4AJ3E1VSS91VSS92VSS93VSS94VSS95VSS96VSS97VSS98VSS99+1.5VSN6L6L2K5L3L7K4J5+VCCP1AGP_AD28 AC25AGP_AD29 AC24AGP_AD30 AC22AGP_AD31 AD24AC