From mboxrd@z Thu Jan 1 00:00:00 1970 Mime-Version: 1.0 Message-Id: In-Reply-To: <200003151243.MAA30200@hyperion.valhalla.net> References: <200003151243.MAA30200@hyperion.valhalla.net> Date: Thu, 16 Mar 2000 00:16:48 -0800 To: "Iain Sandoe" , Benjamin Herrenschmidt From: "Timothy A. Seufert" Subject: Re: Different Mac Models. Cc: linuxppc-dev@lists.linuxppc.org Content-Type: text/plain; charset="us-ascii" ; format="flowed" Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: At 12:43 PM +0000 3/15/00, Iain Sandoe wrote: >> >>>To nitpick, the chip in question (the PMU) is really a power >>>management chip which also happens to implement ADB in older models. >>> >>>The Sawtooth, iBook, and Pismo all use a new PMU design which is the >>>first major revision in many years. It probably doesn't actually >>>have any pins dedicated to a physical ADB bus anymore, but a virtual >>>ADB bus implemented in the PMU's firmware is quite possible. >> >> Yes, that's how it's implemented: software emulation of ADB in the PMU. >> To my knowledge it's only in the firmware of the iBook and PowerBook PMU, >> not in the new iMac nor in the G4 PMU. > >firmware as in local (to the PMU) flash/rom... Firmware local to the PMU. Previous to the new PMU, the firmware was in mask ROM, but the new PMU used in Uni-N based systems has flash so it can be updated. In both cases the ROM / flash is integrated into the PMU die, separate from the main system firmware ROM/flash. Tim Seufert ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/