diff options
| author | jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-08-03 04:51:51 +0000 |
|---|---|---|
| committer | jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-08-03 04:51:51 +0000 |
| commit | 5d69a524f81f234b3fbc41d49ba18d6f6886baba (patch) | |
| tree | b71312bf7f1e8d10fef0f3ac6f28784065e73e72 /usrp/firmware/lib/delay.c | |
Houston, we have a trunk.
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3122 221aa14e-8319-0410-a670-987f0aec2ac5
Diffstat (limited to 'usrp/firmware/lib/delay.c')
| -rw-r--r-- | usrp/firmware/lib/delay.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/usrp/firmware/lib/delay.c b/usrp/firmware/lib/delay.c new file mode 100644 index 0000000000..c8bad7f2ca --- /dev/null +++ b/usrp/firmware/lib/delay.c @@ -0,0 +1,76 @@ +/* -*- c++ -*- */ +/* + * Copyright 2003 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio 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, or (at your option) + * any later version. + * + * GNU Radio 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 GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +/* + * Delay approximately 1 microsecond (including overhead in udelay). + */ +static void +udelay1 (void) _naked +{ + _asm ; lcall that got us here took 4 bus cycles + ret ; 4 bus cycles + _endasm; +} + +/* + * delay for approximately usecs microseconds + */ +void +udelay (unsigned char usecs) +{ + do { + udelay1 (); + } while (--usecs != 0); +} + + +/* + * Delay approximately 1 millisecond. + * We're running at 48 MHz, so we need 48,000 clock cycles. + * + * Note however, that each bus cycle takes 4 clock cycles (not obvious, + * but explains the factor of 4 problem below). + */ +static void +mdelay1 (void) _naked +{ + _asm + mov dptr,#(-1200 & 0xffff) +002$: + inc dptr ; 3 bus cycles + mov a, dpl ; 2 bus cycles + orl a, dph ; 2 bus cycles + jnz 002$ ; 3 bus cycles + + ret + _endasm; +} + +void +mdelay (unsigned int msecs) +{ + do { + mdelay1 (); + } while (--msecs != 0); +} + + |