From blaurent@titech.ac.jp Sun Jun 04 00:54:10 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!titech!blaurent From: blaurent@titech.ac.jp (Brian Laurent) Newsgroups: comp.sys.m68k Subject: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jun04.005410.6588@titech.ac.jp> Date: Sun, 04 Jun 1995 00:54:10 GMT Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: Netscape 1.1N Lines: 10 Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. By setting up Paula's audio DMA to double-buffer incoming 8-bit samples, the 68020 has plenty of cycles left for the Costas loop. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Brian Laurent -- Tokyo Institute of Technology Computer Centre "Do not worship the copy." From msouza@cern.ch Sun Jun 04 15:45:10 1995 Path: ashpoly!cascade!brgate!saturno!cern!msouza From: msouza@cern.ch (Mike Souza) Newsgroups: comp.sys.m68k Subject: Re: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jun04.154510.2722@cern.ch> Date: Sun, 04 Jun 1995 15:45:10 GMT References: <1995Jun04.005410.6588@titech.ac.jp> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Jun04.005410.6588@titech.ac.jp>, blaurent@titech.ac.jp (Brian Laurent) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Mike Souza *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0 From aeriksson@kiae.su Sun Jun 04 18:17:10 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!kiae!aeriksson From: aeriksson@kiae.su (Anton Eriksson) Newsgroups: comp.sys.m68k Subject: Re: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jun04.181710.1927@kiae.su> Date: Sun, 04 Jun 1995 18:17:10 GMT References: <1995Jun04.005410.6588@titech.ac.jp> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jun04.005410.6588@titech.ac.jp>, blaurent@titech.ac.jp (Brian Laurent) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Anton Eriksson Opinions expressed are solely my own and not those of Kurchatov Institute of Atomic Energy, Moscow. ------------------------------------------------------------