From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3911C380.27BFAB85@motorola.com> Date: Thu, 04 May 2000 13:37:52 -0500 From: "Richard Hendricks" MIME-Version: 1.0 To: Dan Malek CC: Kim Jørgensen Subject: Re: Problem with MPC823 LCD driver References: <819E3E914E0AD11194DE00805F0D100B0138B852@fbi.infocom.dk> <3911A489.F4A255F6@embeddededge.com> Content-Type: text/plain; charset=iso-8859-1 Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: That could be it. One obvious indicator is that without LCD and the caches disabled, everything works fine. If it breaks with the caches turned on, check your UPM burst tables. This is where most mistakes occur. Also, be sure to bring all the UPM signals back high at the end of your transactions. Dan Malek wrote: > > Kim Jørgensen wrote: > > > I got a custom MPC823E board, and I want to use a LCD display with Linux. > > Get the logic analyzer on the bus....... > > > Can anyone tell me what is wrong, and how to solve this? > > I can make a few guesses. This has nothing to do with Math Emulation, > and everything to do with fetching the proper instructions into the > core. The LCD controller is a heavy-duty DMA controller that has > priority over everything to ensure it can keep the display updated > from system memory. Since the controller performs large burst mode > operations, this is a classic example of memory controller or memory > interface problems. I suspect the memory timing isn't correct and the > instructions are just bad memory cycles that can't be properly > decoded. > > -- Dan > -- MPC823 Applications Engineering Development ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/