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*IRQ1 assigned to anything?
Posted: Fri Sep 25, 2009 12:39 pm
by Ridgeglider
Could the NB folks confirm whether the *IRQ1 pin ( J2[43] on most modules ) is used in any of the platform code? I believe it is currently unused although I believe I saw reference to a potential upcoming use associated with the EFFS and SD card drivers. I'd like to use it in a project, but not if it is (or will be) reserved for some future system resources, for example the way *IRQ3 looks like it's been associated with possible use with the RTC alarm functions. (Thanks Larry!)
Re: *IRQ1 assigned to anything?
Posted: Fri Sep 25, 2009 2:08 pm
by lgitlitz
IRQ #5 is currently being used as the Card Detect input for the SD Card interface. This IRQ is just being used as a GPIO input and can really be switched to any available GPIO. A simple modification to the function "int get_cd( void )" in mmc_mcf.cpp can free up this IRQ in software. You also would have to change the dev board hardware so the CD signal is connected to the new GPIO.
IRQ #3 is reserved as a SDIO interrupt. This is being used on our soon to be released WiFi adapter. This might be best left alone if you plan on using WiFi, otherwise it is not used.
IRQ #1 is connected to both the IRQ button and the RTC IRQ line on the Dev-Board. The driver for the RTC now has alarm functions that use this IRQ but it should not be hard to change this code for any of the other IRQs. Both the button and the RTC have open drain signals for the IRQ... they pull the signal low when active, hiz when inactive. You can connect other open collector signals to this IRQ with the RTC still connected.
-Larry