From 0eff7675999eef0c1c3175a33e37d8d519cf7fa0 Mon Sep 17 00:00:00 2001 From: Nicolas Schodet Date: Wed, 7 Apr 2010 23:50:51 +0200 Subject: digital/io/src: add US distance sensor support, refs #113 --- digital/io/src/usdist.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 digital/io/src/usdist.c (limited to 'digital/io/src/usdist.c') diff --git a/digital/io/src/usdist.c b/digital/io/src/usdist.c new file mode 100644 index 00000000..342358ea --- /dev/null +++ b/digital/io/src/usdist.c @@ -0,0 +1,64 @@ +/* usdist.c */ +/* io - Input & Output with Artificial Intelligence (ai) support on AVR. {{{ + * + * Copyright (C) 2010 Nicolas Schodet + * + * APBTeam: + * Web: http://apbteam.org/ + * Email: team AT apbteam DOT org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * }}} */ +#include "common.h" +#include "usdist.h" + +#include "modules/adc/adc.h" +#include "modules/utils/utils.h" +#include "io.h" + +uint16_t usdist_mm[USDIST_NB]; + +void +usdist_init (void) +{ + adc_init (); +} + +void +usdist_update (void) +{ + uint8_t i; + /* Simple algorithm, just make a conversion for every sensor. This should + * be improved because it takes too long. */ + for (i = 0; i < USDIST_NB; i++) + { + adc_start (i); + while (!adc_checkf ()) + ; + uint16_t v = adc_read (); + /* Our sensors return a value between 1 and 5 V proportional to the + * distance between calibrated values. */ + if (v <= 1024 / 5) + usdist_mm[i] = USDIST_MM_MIN; + else + usdist_mm[i] = USDIST_MM_MIN + + (uint32_t) (v - 1024 / 5) * (USDIST_MM_MAX - USDIST_MM_MIN) + / (4 * 1024 / 5); + if (usdist_mm[i] >= USDIST_MM_TOO_FAR) + usdist_mm[i] = 0xffff; + } +} + -- cgit v1.2.3