On Wed, 2005-03-30 at 21:37 -0800, nobin matthew wrote: > The Platform is Arcom Viper borad(with support for > PC104), This is a Xscale, Little endian Platform. If you contact Arcom technical support on either euro-support@xxxxxxxxx or us-support@xxxxxxxxx then they will be able to help you with any problems you are having with the VIPER platform. The answer to your question is that the ISA I/O address space is mapped at address 0xf7000000 on the VIPER so the address you need to use with inb() and outb() is actually 0xf7000300 rather than just 0x300. This is described in the Quickstart manual that ships with the development kit. There is also a document describing this (because it is an FAQ) in the support site http://www.arcom.com/support/faq/Embed_Sys.htm#Linux Cheers, Ian. -- Ian Campbell, Senior Design Engineer Web: http://www.arcom.com Arcom, Clifton Road, Direct: +44 (0)1223 403 465 Cambridge CB1 7EA, United Kingdom Phone: +44 (0)1223 411 200 -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/