
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">


<HTML><HEAD>


<META http-equiv=Content-Type content="text/html; charset=gb2312">


<META content="MSHTML 6.00.6000.16809" name=GENERATOR><LINK 


href="BLOCKQUOTE{margin-Top: 0px; margin-Bottom: 0px; margin-Left: 2em}" 


rel=stylesheet></HEAD>


<BODY style="FONT-SIZE: 10pt; MARGIN: 10px; FONT-FAMILY: verdana">


<DIV>Hi,every one,</DIV>


<DIV>&nbsp;</DIV>


<DIV>&nbsp;</DIV>


<DIV>I want to drive the&nbsp;&nbsp;Rcomp&nbsp;circuit for ixp460, because I 


found that the ixp460 could not power up on low temperature(-40 degree).&nbsp; I 


want to add those code on start.s, follow is the instruction from ixp460 


developer's manual. Does anyone can help me realize those code from No.4 to 


No.6?</DIV>


<DIV>&nbsp;</DIV>


<DIV>&nbsp;</DIV>


<DIV>&nbsp;</DIV>


<DIV>&nbsp;</DIV>


<DIV>&nbsp;</DIV>


<DIV>Instrction:</DIV>


<DIV>


<DIV>1.&nbsp;The&nbsp;MCU&nbsp;applies&nbsp;the&nbsp;clock&nbsp;DDRI_CK[2:0]&nbsp;at&nbsp;power&nbsp;up&nbsp;along&nbsp;with&nbsp;system&nbsp;power</DIV>


<DIV>(clock&nbsp;frequency&nbsp;unknown).</DIV>


<DIV>2.&nbsp;The&nbsp;MCU&nbsp;must&nbsp;stabilize&nbsp;DDRI_CK[2:0]&nbsp;within&nbsp;100&nbsp;┢s&nbsp;after&nbsp;power&nbsp;stabilizes.</DIV>


<DIV>3.&nbsp;The&nbsp;MCU&nbsp;holds&nbsp;the&nbsp;following&nbsp;control&nbsp;inputs&nbsp;inactive:</DIV>


<DIV>DDRI_RAS_N,&nbsp;DDRI_CAS_N,&nbsp;DDRI_WE_N,&nbsp;DDRI_CS_N[1:0]</DIV></DIV>


<DIV>


<DIV>The&nbsp;MCU&nbsp;then&nbsp;places&nbsp;all&nbsp;of&nbsp;the&nbsp;following&nbsp;data&nbsp;outputs&nbsp;and&nbsp;strobes&nbsp;in&nbsp;the&nbsp;High-Z</DIV>


<DIV>state:</DIV>


<DIV>DDRI_DQS[4:0],&nbsp;DDRI_DQ[31:0],&nbsp;DDR_CB[7:0]</DIV></DIV>


<DIV>&nbsp;</DIV>


<DIV>


<DIV><FONT 


color=#ff0000>4.&nbsp;The&nbsp;MCU&nbsp;then&nbsp;performs&nbsp;sixteen&nbsp;RCOMP&nbsp;calibration&nbsp;cycles&nbsp;which&nbsp;take&nbsp;an&nbsp;additional</FONT></DIV>


<DIV><FONT 


color=#ff0000>34&nbsp;ms.&nbsp;Software&nbsp;MUST&nbsp;wait&nbsp;until&nbsp;this&nbsp;time&nbsp;has&nbsp;elapsed&nbsp;before&nbsp;continuing&nbsp;with&nbsp;DDRI</FONT></DIV>


<DIV><FONT color=#ff0000>SDRAM&nbsp;initialization.</FONT></DIV>


<DIV><FONT 


color=#ff0000>5.&nbsp;Software&nbsp;overwrites&nbsp;the&nbsp;default&nbsp;value&nbsp;of&nbsp;register&nbsp;DDR_RCOMP_CSR3&nbsp;(Hex&nbsp;Offset</FONT></DIV>


<DIV><FONT 


color=#ff0000>Address&nbsp;=&nbsp;0x0CC00&nbsp;F570)&nbsp;with&nbsp;a&nbsp;new&nbsp;value&nbsp;of&nbsp;0x0000&nbsp;1000.</FONT></DIV>


<DIV><FONT 


color=#ff0000>6.&nbsp;Software&nbsp;overwrites&nbsp;the&nbsp;default&nbsp;value&nbsp;of&nbsp;register&nbsp;DDR_DRIVE3&nbsp;(Hex&nbsp;Offset&nbsp;Address</FONT></DIV>


<DIV><FONT 


color=#ff0000>=&nbsp;0x0CC00&nbsp;F5AC)&nbsp;with&nbsp;a&nbsp;new&nbsp;value&nbsp;of&nbsp;0x0002&nbsp;08F0.</FONT></DIV></DIV>


<DIV>&nbsp;</DIV>


<DIV>


<DIV>7.&nbsp;Software&nbsp;disables&nbsp;the&nbsp;refresh&nbsp;counter&nbsp;by&nbsp;setting&nbsp;the&nbsp;RFR&nbsp;to&nbsp;zero.</DIV>


<DIV>8.&nbsp;Software&nbsp;issues&nbsp;one&nbsp;NOP&nbsp;cycle&nbsp;after&nbsp;the&nbsp;200&nbsp;us&nbsp;device&nbsp;deselect.&nbsp;A&nbsp;NOP&nbsp;is</DIV>


<DIV>accomplished&nbsp;by&nbsp;setting&nbsp;the&nbsp;SDIR&nbsp;to&nbsp;00112.&nbsp;The&nbsp;MCU&nbsp;asserts&nbsp;DDRI_CKE[1:0]&nbsp;with</DIV>


<DIV>the&nbsp;NOP.</DIV>


<DIV>9.&nbsp;Software&nbsp;issues&nbsp;a&nbsp;precharge-all&nbsp;command&nbsp;to&nbsp;the&nbsp;DDRI&nbsp;SDRAM&nbsp;interface&nbsp;by&nbsp;setting</DIV>


<DIV>the&nbsp;SDIR&nbsp;to&nbsp;00102.</DIV>


<DIV>10.&nbsp;Software&nbsp;issues&nbsp;an&nbsp;extended-mode-register-set&nbsp;command&nbsp;to&nbsp;enable&nbsp;the&nbsp;DLL&nbsp;by</DIV>


<DIV>writing&nbsp;01002&nbsp;to&nbsp;the&nbsp;SDIR.&nbsp;The&nbsp;MCU&nbsp;supports&nbsp;the&nbsp;following&nbsp;DDRI&nbsp;SDRAM&nbsp;mode</DIV>


<DIV>parameters:</DIV></DIV>


<DIV>


<DIV>11.&nbsp;After&nbsp;waiting&nbsp;Tmrd&nbsp;cycles,&nbsp;software&nbsp;issues&nbsp;a&nbsp;mode-register-set&nbsp;command&nbsp;by&nbsp;writing</DIV>


<DIV>00012&nbsp;to&nbsp;the&nbsp;SDIR&nbsp;to&nbsp;program&nbsp;the&nbsp;DDRI&nbsp;SDRAM&nbsp;parameters&nbsp;and&nbsp;to&nbsp;reset&nbsp;the&nbsp;DLL.</DIV>


<DIV>The&nbsp;MCU&nbsp;supports&nbsp;the&nbsp;following&nbsp;DDRI&nbsp;SDRAM&nbsp;mode&nbsp;parameters:</DIV></DIV>


<DIV>


<DIV>12.&nbsp;After&nbsp;waiting&nbsp;Tmrd&nbsp;cycles,&nbsp;software&nbsp;issues&nbsp;a&nbsp;precharge-all&nbsp;command&nbsp;to&nbsp;the&nbsp;DDRI</DIV>


<DIV>SDRAM&nbsp;interface&nbsp;by&nbsp;setting&nbsp;the&nbsp;SDIR&nbsp;to&nbsp;00102.</DIV>


<DIV>13.&nbsp;After&nbsp;waiting&nbsp;Trp&nbsp;cycles,&nbsp;software&nbsp;provides&nbsp;two&nbsp;auto-refresh&nbsp;cycles.&nbsp;An&nbsp;auto-refresh</DIV>


<DIV>cycle&nbsp;is&nbsp;accomplished&nbsp;by&nbsp;setting&nbsp;the&nbsp;SDIR&nbsp;to&nbsp;01102.&nbsp;Software&nbsp;must&nbsp;ensure&nbsp;at&nbsp;least</DIV>


<DIV>Trfc&nbsp;cycles&nbsp;between&nbsp;each&nbsp;auto-refresh&nbsp;command.</DIV>


<DIV>14.&nbsp;Following&nbsp;the&nbsp;second&nbsp;auto-refresh&nbsp;cycle,&nbsp;software&nbsp;must&nbsp;wait&nbsp;Trfc&nbsp;cycles.&nbsp;Then,</DIV>


<DIV>software&nbsp;issues&nbsp;a&nbsp;mode-register-set&nbsp;command&nbsp;by&nbsp;writing&nbsp;to&nbsp;the&nbsp;SDIR&nbsp;to&nbsp;program&nbsp;the</DIV>


<DIV>DDRI&nbsp;SDRAM&nbsp;parameters&nbsp;without&nbsp;resetting&nbsp;the&nbsp;DLL&nbsp;by&nbsp;writing&nbsp;00002&nbsp;to&nbsp;the&nbsp;SDIR.</DIV></DIV>


<DIV>


<DIV>15.&nbsp;The&nbsp;MCU&nbsp;may&nbsp;issue&nbsp;a&nbsp;row-activate&nbsp;command&nbsp;Tmrd&nbsp;cycles&nbsp;after&nbsp;the&nbsp;mode-register-set</DIV>


<DIV>command.</DIV>


<DIV>16.&nbsp;Software&nbsp;re-enables&nbsp;the&nbsp;refresh&nbsp;counter&nbsp;by&nbsp;setting&nbsp;the&nbsp;RFR&nbsp;to&nbsp;the&nbsp;required&nbsp;value.</DIV>


<DIV>The&nbsp;waveform&nbsp;in&nbsp;Figure&nbsp;109&nbsp;illustrates&nbsp;the&nbsp;DDRI&nbsp;SDRAM&nbsp;initialization&nbsp;sequence.</DIV></DIV>


<DIV>&nbsp;</DIV>


<DIV><FONT face=Verdana size=2></FONT>&nbsp;</DIV>


<DIV align=left><FONT face=Verdana color=#c0c0c0 size=2>2009-05-18 


</FONT></DIV><FONT face=Verdana size=2>


<HR style="WIDTH: 122px; HEIGHT: 2px" align=left SIZE=2>


<DIV><FONT face=Verdana color=#c0c0c0 size=2><SPAN>


<DIV>


<DIV><FONT size=5>&nbsp;<FONT color=#0000ff>&nbsp;&nbsp; 벋&nbsp; 


쐼</FONT></FONT></DIV>


<DIV><FONT color=#0000ff size=5>13810607876</FONT></DIV>


<DIV><FONT color=#0000ff size=5>010-62771694</FONT></DIV>


<DIV>&nbsp;</DIV></DIV></SPAN></FONT></DIV></FONT></BODY></HTML>