From: Daniel O'S. <da...@oz...> - 2007-03-18 11:43:36
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...looking at the PXA270's 121 GPIO's and their alternate functions, it seems to me that certain functions must conflict and be mutually exclusive as they share pin assignments - is there any information on this that would save me the trouble of manually comparing all the data in the alternate function tables to find out? thanks! |
From: Pascal <pa...@pa...> - 2007-03-18 12:46:47
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Daniel O'Shea wrote: > ...looking at the PXA270's 121 GPIO's and their alternate functions, it > seems to me that certain functions must conflict and be mutually > exclusive as they share pin assignments Do you have a specific example ? My understanding is that some alternate functions can be assigned to one of *several* GPIOs. For example GPIO<48> has both CIF_DD<5> and nPOE, so you may think that CIF and PCMCIA are mutually exclusive. But CIF_DD<5> can also be routed to GPIO<82>, GPIO<91> or GPIO<94>. As far as I know the reference table is in the PXA270 EMTS document. What we really need is a SAT solver to find out whether there exists an assignment that enables all functions simultaneously :-) Pascal |
From: Daniel O'S. <da...@oz...> - 2007-03-18 13:32:09
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Pascal wrote: > Daniel O'Shea wrote: >>...looking at the PXA270's 121 GPIO's and their alternate functions, it >>seems to me that certain functions must conflict and be mutually >>exclusive as they share pin assignments > > Do you have a specific example ? Well, for example, the FFUART and USB_P2 seem to occupy a lot of the same GPIO's, so if you wanted to use both then it limits the available functions remaining... > My understanding is that some alternate functions can be assigned to > one of *several* GPIOs. For example GPIO<48> has both CIF_DD<5> and > nPOE, so you may think that CIF and PCMCIA are mutually exclusive. > But CIF_DD<5> can also be routed to GPIO<82>, GPIO<91> or GPIO<94>. > > As far as I know the reference table is in the PXA270 EMTS document. > What we really need is a SAT solver to find out whether there exists > an assignment that enables all functions simultaneously :-) > > Pascal |
From: Craig H. <cr...@gu...> - 2007-03-18 17:11:09
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On Mar 18, 2007, at 4:43 AM, Daniel O'Shea wrote: > ...looking at the PXA270's 121 GPIO's and their alternate > functions, it > seems to me that certain functions must conflict and be mutually > exclusive as they share pin assignments - is there any information on > this that would save me the trouble of manually comparing all the data > in the alternate function tables to find out? thanks! There's some excel spreadsheet which an Intel guy gave me one time, but IMO it's more confusing to use than just browsing the table in the programmer's guide. If you're wanting to use the verdex, you'll be a little more limited than the "raw" PXA270 too, because only some signals come off on some connectors. If you look at a chart like <http://docwiki.gumstix.com/120pin_connector_chart>, the way it's laid out is to basically pick "default" settings for the GPIO lines (the Signal column when the line is a GPIO in alt fn mode) -- you should try and use that as the base setup and then modify from there to minimize collateral impact. C |