Path: utzoo!utgpu!bnr-vpa!bruce From: bruce@bnr-vpa.UUCP (Bruce Townsend) Newsgroups: comp.sys.hp Subject: Re: GPIO (AFI) Interface Problem with HP9000s825 R2.0 Message-ID: <106@bnr-vpa.UUCP> Date: 9 Dec 88 14:48:17 GMT References: <104@bnr-vpa.UUCP> <1310003@hpdstma.HP.COM> Reply-To: bruce@bnr-vpa.UUCP (Bruce Townsend) Organization: Bell-Northern Research, Ottawa, Ontario Lines: 13 In article <1310003@hpdstma.HP.COM> dc@hpdstma.HP.COM (Daniel Cordey) writes: >20 ms seems too long...Is your process runing at a real-time priority ? > No; perhaps if it were, the gap could be reduced to 10ms? 5ms? even 1ms? That is still too long; the samples are presented/read by the peripheral at a regular rate up to 100K words/sec. That means that the interval between any given pair of sample read/writes can be no longer than 10 usec. Clearly, continuous DMA into physical memory is required. -- Bruce Townsend (bnr-vpa!bruce) Phone: (613) 763-3008 Bell-Northern Research Usenet: {utzoo, utcs}!bnr-vpa!bruce P.O. Box 3511, Station C, Ottawa, Ontario, Canada, K1Y 4H7