From: Dave H. <dhy...@gm...> - 2005-10-26 16:30:33
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Hi elynum, > I'm currently using a xilinx fpga with a powerpc core inside of it. I'm = trying to figure out how to toggle an LED from the operating system. Basica= lly how to hook up my low level driver to a high level driver. I expect to= use a gumstix board soon, so this is good practice for me. I know doing t= his should be similar to how people do these things on the gumstix board. = On the FPGA board it seems you have to put this in your makefile for buildi= ng the kernel. Is it the same for gumstix? Are there any documentation as= far as if you have a gumstix board and you want to toggle LED lines or swi= tches from a linux OS how would you go about achieving this that gives a gr= eat explanation of this. You'll probably want to read through this book: http://www.oreilly.com/catalog/linuxdrive3/ which you can view online as well: http://www.oreilly.com/catalog/linuxdrive3/book/index.csp The general technique is to register a driver and implement an ioctl call. There are other mechanisms, like the proc file system (which is what the current GPIO "driver" uses). I'm not quite sure what you mean by low-level and high-level drivers. There is kernel space and user space code, and within the kernel space you have 3 different "levels": ISR's, tasklet (some embedded OS's would call these software ISR's) and threads (either kernel threads or acting on behalf of a user mode thread). -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |