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authorJérémy Dufour2009-05-16 01:23:06 +0200
committerJérémy Dufour2009-05-16 01:23:06 +0200
commit890eb720d5c6194d84f5467c32b017b792cad42f (patch)
tree24910c6e92990a6a1077d6d6ba606efe8ec2613c /digital/avr/modules
parentd9071896298d040d8c00b8e45812dc77636f500c (diff)
* digital/avr/modules/utils:
- add a function to compute CRC.
Diffstat (limited to 'digital/avr/modules')
-rw-r--r--digital/avr/modules/utils/crc.h76
-rw-r--r--digital/avr/modules/utils/test/Makefile3
-rw-r--r--digital/avr/modules/utils/test/test_crc.c40
3 files changed, 118 insertions, 1 deletions
diff --git a/digital/avr/modules/utils/crc.h b/digital/avr/modules/utils/crc.h
new file mode 100644
index 00000000..04a3eed8
--- /dev/null
+++ b/digital/avr/modules/utils/crc.h
@@ -0,0 +1,76 @@
+#ifndef crc_h
+#define crc_h
+/* crc.h */
+/* crc - Compute CRC for data (CRC on 8 bits). {{{
+ *
+ * Copyright (C) 2009 Dufour Jérémy
+ *
+ * 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.
+ *
+ * }}} */
+
+#ifndef HOST
+#include <util/crc16.h>
+#endif
+
+#ifdef HOST
+/**
+ * CRC i-button, 8-bit (Dallas/Maxim) for host.
+ */
+uint8_t
+_crc_ibutton_update (uint8_t crc, uint8_t data)
+{
+ uint8_t i;
+
+ crc = crc ^ data;
+ for (i = 0; i < 8; i++)
+ {
+ if (crc & 0x01)
+ crc = (crc >> 1) ^ 0x8C;
+ else
+ crc >>= 1;
+ }
+ return crc;
+}
+#endif
+
+/**
+ * Compute CRC.
+ * @param data the data on which to compute CRC.
+ * @param length the length of data (in byte).
+ * @return the computed CRC.
+ */
+static inline uint8_t
+crc_compute (uint8_t *data, uint8_t length)
+{
+ uint8_t i, crc;
+ /* Sanity check. */
+ if (!data)
+ return 0;
+ /* For each data byte. */
+ for (i = 0, crc = 0; i < length; i++)
+ {
+ /* Compute CRC. */
+ crc = _crc_ibutton_update (crc, data[i]);
+ }
+ /* Return computed CRC. */
+ return crc;
+}
+
+#endif /* crc_h */
diff --git a/digital/avr/modules/utils/test/Makefile b/digital/avr/modules/utils/test/Makefile
index 783d7922..5724a5e2 100644
--- a/digital/avr/modules/utils/test/Makefile
+++ b/digital/avr/modules/utils/test/Makefile
@@ -1,9 +1,10 @@
BASE = ../../..
-PROGS = test_utils test_byte
+PROGS = test_utils test_byte test_crc
AVR_PROGS = test_byte_methods
test_utils_SOURCES = test_utils.c
test_byte_SOURCES = test_byte.c
test_byte_methods_SOURCES = test_byte_methods.c
+test_crc_SOURCES = test_crc.c
MODULES = utils
CONFIGFILE = avrconfig.h
# atmega8, atmega8535, atmega128...
diff --git a/digital/avr/modules/utils/test/test_crc.c b/digital/avr/modules/utils/test/test_crc.c
new file mode 100644
index 00000000..64b5b7aa
--- /dev/null
+++ b/digital/avr/modules/utils/test/test_crc.c
@@ -0,0 +1,40 @@
+/* test_crc.c */
+/* avr.utils - Utilities AVR module. {{{
+ *
+ * Copyright (C) 2009 Dufour Jérémy
+ *
+ * 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 "modules/utils/crc.h"
+
+int
+main (void)
+{
+ uint8_t test_vector[] = { 0x02, 0x1c, 0xb8, 0x01, 0, 0, 0, 0xa2 };
+
+ if (crc_compute (test_vector,
+ sizeof test_vector / sizeof test_vector[0])
+ != 0)
+ return 1;
+ else
+ return 0;
+}