Hi, The past is coming to life again.... I just found the message below that was sent almost a year ago to the LPC2000 forum and I'm just attempting to do the same thing as the original poster. Having looked at this, I have come to the same conclusion as Bill - use XCLK to produce a new derived CS dependent on the address. The question I have is 'how does this affect the required access time for the device'. The timing parameters given in the LPC2294 data sheet don't seem complete enough to make this determination. If I knew the actual point in the cycle when the data had to be valid then it would be easy, but that isn't specified. Anybody have any ideas on this? Andy.. --- In lpc2000@yahoogroups.com, "Bill Knight" <BillK@t...> wrote: > > You can use XCLK to delay CS. That will give the address bus time > to stablize. > > Regards > -Bill Knight > http://www.theARMPatch.com > > > On Mon, 01 Nov 2004 23:18:53 -0000, Damon Kelly wrote: > > > > I'm considering the LPC221x for a data acquisition device, but I > need multi-megabytes of SRAM (say, 16MB), and several parallel > devices. I'll need multiple devices on the same memory channel, at > different addresses. > Looking at the timing digrams for the address bus, I can't see how > to reliably decode the address bus to generate extra CS signals: CS > and OE can go low before OR after the address lines settle. > > Any suggestions on how to qualify CS, OE or WE to allow multiple > devices on the bus? >
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Re: External address decoding
2005-10-24 by grapevinetech
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