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Re: question about pmc card



Hu Jianfeng,

If you do not implement BUSMODE signals your device will not
be compliant with the PMC specification.

What your device needs to do to be compliant is:
if BUSMODE[4:2] is LLL then drive BUSMODE[1] low and hold your device tristate.
if BUSMODE[4:2] is LLH then drive BUSMODE[1] low.
in all other cases drive BUSMODE[1] high.

The typical method of tristating your device is to hold it in reset state.

That said, it is my experience that many, if not most, PMC devices
do not implement, or only partially implement the BUSMODE signals.

If you wish to be non-compliant and not implement BUSMODE signals
you are probably safest to at least drive BUSMODE[1] low and not
connect BUSMODE[4:2].

-Ivor


At 09:30 AM 12/26/01 +0800, "MTD Hu JianFeng" <HuJF@sbell.com.cn> wrote:
>Dear friends,
>
>     I want to implement a pmc mezzanine card ,but not use the busmode1#;
>busmode 2#,busmode 3#,busmode 4# signals.
>how can i put them ?
>let them unconnected on the card or other state?
>
>thanks in advance
>
>
>
>Best regards  !
>-----------------------------------------------
>Hu Jianfeng
>Electronics  Engineer
>
>MTD 7, Shanghai Bell Co., Ltd.
>Address: 9 Floor, No.525, North Xizang Road 
>                Shanghai
>                China
>Zip Code: 200070
>Email: Hujf@sbell.com.cn
>-----------------------------------------------
>
><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
><HTML>
><HEAD>
><TITLE>question about pmc card</TITLE>
></HEAD>
><BODY>
><!-- Converted from text/rtf format -->
>
><P><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="Arial">Dear friends,</FONT></SPAN>
></P>
>
><P><SPAN LANG="zh-cn"><FONT SIZE=2
FACE="Arial">&nbsp;&nbsp;&nbsp;&nbsp;</FONT> <FONT SIZE=2 FACE="SimSun">I
want to implement a pmc mezzanine card</FONT> <FONT SIZE=2
FACE="SimSun">,</FONT><FONT SIZE=2 FACE="SimSun">but not use the
busmode1#;</FONT></SPAN>
>
><BR><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="SimSun">busmode 2#,busmode
3#,busmode 4# signals.</FONT></SPAN>
>
><BR><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="SimSun">how can i put them
?</FONT></SPAN>
>
><BR><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="SimSun">let them unconnected on
the card or other state?</FONT></SPAN>
></P>
>
><P><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="">thanks in advance</FONT></SPAN>
></P>
><BR>
><BR>
>
><P><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="">Best regards&nbsp; !<BR>
></FONT><FONT SIZE=2
FACE="">-----------------------------------------------</FONT></SPAN>
>
><BR><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="Arial">Hu Jianfeng<BR>
></FONT><FONT SIZE=2 FACE="Arial">Electronics&nbsp; Engineer</FONT></SPAN>
></P>
>
><P><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="Arial">MTD 7, Shanghai Bell Co.,
Ltd.<BR>
>Address: 9 Floor, No.525, North Xizang Road </FONT></SPAN>
>
><BR><SPAN LANG="zh-cn"><FONT SIZE=2
FACE="Arial">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb
sp;&nbsp;&nbsp;&nbsp;&nbsp; Shanghai</FONT></SPAN>
>
><BR><SPAN LANG="zh-cn"><FONT SIZE=2
FACE="Arial">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb
sp;&nbsp;&nbsp;&nbsp;&nbsp; China<BR>
>Zip Code: 200070</FONT></SPAN>
>
><BR><SPAN LANG="zh-cn"><FONT SIZE=2 FACE="Arial">Email: Hujf@sbell.com.cn<BR>
></FONT><FONT SIZE=2
FACE="">-----------------------------------------------</FONT></SPAN>
></P>
>
></BODY>
></HTML>