Date: Wed, 5 Aug 1998 12:23:55 +0200 From: Ignatios Souvatzis <ignatios@theory.cs.uni-bonn.de> To: freebsd-isdn@FreeBSD.ORG Subject: Re: Amiga ISDN boards: take two Message-ID: <19980805122355.H23444@cs.uni-bonn.de> In-Reply-To: <no.id>; from Martin Recktenwald on Wed, Aug 05, 1998 at 10:26:22AM %2B0200
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On Wed, Aug 05, 1998 at 10:26:22AM +0200, Martin Recktenwald wrote: > Ignatios Souvatzis <is@jocelyn.rhein.de> writes: > > > - HSCX_A RTS pin is connected to ISAC RESET, and needs to be set to make > > the ISAC usable. > > > Now thatīs weird. No. - The ISAC comes out of the reset condition with interupts enabled - 68k interupts are level interupts. so, if you didn't somehow block the interupts, the first person calling you on the same S0 bus after reset, but before the driver is installed, would freeze the machine. Now, the HSCX RTS output is guaranteed to be at 0 level after a reset, and is not needed for ISDN applications. So, if you don't want to add additional hardware to an otherwise very small board (its 4 chips, and the s0 transformer circuitry), it seems very natural to me to abuse that one. Btw: from browsing the other backends (hm... I think Teles S08 was one), I noticed that some other boards have special reset circuitry, too... only they use additional hardware. Regards, Ignatios To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message
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