<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">fyi<br><div><br><div>Begin forwarded message:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>From: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Andy Green <<a href="mailto:andy@openmoko.com">andy@openmoko.com</a>></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>Date: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">March 19, 2008 7:43:02 AM GMT+08:00</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span class="Apple-style-span" style="-webkit-text-stroke-width: -1; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>Subject: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica"><b>Re: Adding a system management MPU</b></font></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div> </div>-----BEGIN PGP SIGNED MESSAGE-----<br>Hash: SHA1<br><br>Somebody in the thread at some point said:<br><blockquote type="cite">Andy Green wrote:<br></blockquote><blockquote type="cite"><blockquote type="cite">There is a plan to basically put the debug board FTDI chip on the<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">mainboard for JTAG / debrick purposes, along with a micro USB conn that<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">isn't accessible without opening the case. So we discard the debug<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">board as a "product" and all phones expose a "USB UART" console and JTAG<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">if you want it.<br></blockquote></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I would fear the added cost of the FTDI chip - it's also ugly to force<br></blockquote><blockquote type="cite">the user to open the case.<br></blockquote><br>Well, IIRC it was $3.80 / 1K, no doubt it is cheaper for FIC. We also<br>don't have to deal with the debug board, connector, or cables any more<br>to balance it a bit. Issues around the level of paranoia and protection<br>otherwise needed for built-in debricking (eg, write-once at factory<br>memory now found in GTA02) are solved by this too -- and hackability<br>"built-in" is a feature for this product AIUI. But I take your points.<br><br><blockquote type="cite">In terms if de-bricking I could imagine to expose the RFCOMM-interface<br></blockquote><blockquote type="cite">of the Bluetooth chip<br></blockquote><br><blockquote type="cite">I decided in my EBook design to stick to a discrete CSR Bluecore4 chip<br></blockquote><blockquote type="cite">with UART + USB interface. To debrick it you would for example hold a<br></blockquote><blockquote type="cite">given set of keys that are anyway connected to the MSP and use MSP to<br></blockquote><blockquote type="cite">set the ARM-core into UART boot mode (from ARM core mask ROM)after<br></blockquote><blockquote type="cite">resetting it. The MSP will then upload the stepstone over UART into the<br></blockquote><blockquote type="cite">internal SRAM of your main ARM CPU.<br></blockquote><br>I can see this will work for your design (must be highly impressive to<br>witness), but we would need a new BT module with private UART IF like<br>yours. Also in our case compared to the FTDI solution it wouldn't in<br>itself provide actual JTAG which can be useful for desperate debugging,<br>although we could somehow do it via the MSP GPIO driven by the same BT<br>UART I guess.<br><br>I think it's okay in the end if someone with a brick has to crack the<br>case for a guaranteed fix. $3.80 here and $3 there and pretty soon<br>you're talking real money is true though.<br><br>- -Andy<br>-----BEGIN PGP SIGNATURE-----<br>Version: GnuPG v1.4.7 (GNU/Linux)<br>Comment: Using GnuPG with Fedora - <a href="http://enigmail.mozdev.org">http://enigmail.mozdev.org</a><br><br>iD8DBQFH4FOGOjLpvpq7dMoRAvkjAJ9b/moPMHuOjvIeVlBonsrhGyuuXgCfWCpX<br>McPqTaDUV3Rrh7NT1bGPDCQ=<br>=29dQ<br>-----END PGP SIGNATURE-----<br></blockquote></div><br></body></html>