Hi Dominic Sweetman, Thanks much for your inputs.. > > In R4000 & descendent processors, interrupt > number 7 > > is being used for internal timer interrupt. From > this > > i understand that the timer interrupt is also > maskable > > when the IE bit in status register is cleared. If > > somebody mask this interrupt for a long time > > erroneously, then won't there be a problem in > > maintaining the system time? > > Yes, there may be a long delay. So the standard way > of using the > onchip counter to generate a periodic interrupt is > that the counter > itself is allowed to free-run, keeping accurate > time. > > The 'Compare' register is then incremented by a > fixed amount. > > So long as the interrupt is not delayed by a whole > tick, this keeps > perfect time. > > I'm sure this is described in "See MIPS Run" - do > you have a copy? Yes, i have a copy. Have just started reading this book.. I yet to get into the deep waters of the MIPS.. May i know the purpose of the NMI interrupt and in what way it differ from the timer interrupt. Thanks much, -karthi > -- > Dominic Sweetman > MIPS Technologies Inc > > > ===== The expert at anything was once a beginner ______________________________ / \ O / Karthikeyan.N \ O | Chennai, India. | `\|||/' \ Mobile: +919884104346 / (o o) \ / _ ooO (_) Ooo____________________________________ _____|_____|_____|_____|_____|_____|_____|_____|_ __|_____|_____|_____|_____|_____|_____|_____|____ _____|_____|_____|_____|_____|_____|_____|_____|_ ________________________________________________________________________ Yahoo! Messenger - Communicate instantly..."Ping" your friends today! Download Messenger Now http://uk.messenger.yahoo.com/download/index.html