From 29ea5bbf5b9c3b3679aa40e4ee7029284cb424c6 Mon Sep 17 00:00:00 2001
From: henryk <henryk@6dc7ffe9-61d6-0310-9af1-9938baff3ed1>
Date: Sat, 24 Nov 2007 07:59:42 +0000
Subject: Add load modulation and encoding/decoding code from harald

git-svn-id: https://svn.openpcd.org:2342/trunk@351 6dc7ffe9-61d6-0310-9af1-9938baff3ed1
---
 openpicc/application/iso14443a_manchester.c | 134 ++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 openpicc/application/iso14443a_manchester.c

(limited to 'openpicc/application/iso14443a_manchester.c')

diff --git a/openpicc/application/iso14443a_manchester.c b/openpicc/application/iso14443a_manchester.c
new file mode 100644
index 0000000..efc4baf
--- /dev/null
+++ b/openpicc/application/iso14443a_manchester.c
@@ -0,0 +1,134 @@
+/* ISO14443A Manchester encoder for OpenPICC
+ * (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>
+ *
+ *  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
+ *
+ */
+
+
+/*
+ * Definitions for 106kBps, at sampling clock 1695kHz
+ *
+ * 		bit sample pattern for one bit cycle
+ * 		MSB first		LSB first	hex LSB first
+ * Sequence D	1010101000000000	0000000001010101	0x0055
+ * Sequence E	0000000010101010	0101010100000000	0x5500
+ * Sequence F	1010101010101010	0101010101010101	0x5555
+ *
+ * Logic 1	Sequence D
+ * Logic 0	Sequence E
+ * SOF		Sequence D
+ * EOF		Sequence F
+ *
+ * 212/424/848kBps: BPSK.
+ *
+ * SOF: 32 subcarrier clocks + bit '0'
+ *
+ * SOF:		hex LSB first: 0x55555555 55555555 + bit '0'
+ *
+ * EOF:		even parity of last byte (!)
+ *
+ */
+
+#define MANCHESTER_SEQ_D	0x0055
+#define MANCHESTER_SEQ_E	0x5500
+#define MANCHESTER_SEQ_F	0x5555
+
+#include <errno.h>
+#include <string.h>
+#include "openpicc.h"
+
+static u_int32_t manchester_sample_size(u_int8_t frame_bytelen) __attribute__((unused));
+static u_int32_t manchester_sample_size(u_int8_t frame_bytelen)
+{
+	/* 16 bits (2 bytes) per bit => 16 bytes samples per data byte,
+	 * plus 16bit (2 bytes) parity per data byte
+	 * plus 16bit (2 bytes) SOF plus 16bit (2 bytes) EOF */
+	return (frame_bytelen*18) + 2 + 2;
+
+	/* this results in a maximum samples-per-frame size of 4612 bytes
+	 * for a 256byte frame */
+}
+
+struct manch_enc_state {
+	const char *data;
+	char *samples;
+	u_int16_t *samples16;
+};
+
+static void manchester_enc_byte(struct manch_enc_state *mencs, u_int8_t data) __attribute__((unused));
+static void manchester_enc_byte(struct manch_enc_state *mencs, u_int8_t data)
+{
+	int i;
+	u_int8_t sum_1 = 0;
+
+	/* append 8 sample blobs, one for each bit */
+	for (i = 0; i < 8; i++) {
+		if (data & (1 << i)) {
+			*(mencs->samples16) = MANCHESTER_SEQ_D;
+			sum_1++;
+		} else {
+			*(mencs->samples16) = MANCHESTER_SEQ_E;
+		}
+		mencs->samples16++;
+	}
+	/* append odd parity */
+	if (sum_1 & 0x01)
+		*(mencs->samples16) = MANCHESTER_SEQ_E;
+	else
+		*(mencs->samples16) = MANCHESTER_SEQ_D;
+	mencs->samples16++;
+}
+
+#if 0
+/* Broken? */
+int manchester_encode(char *sample_buf, u_int16_t sample_buf_len, 
+		      const char *data, u_int8_t data_len)
+{
+	int i, enc_size;
+	struct manch_enc_state mencs;
+
+	enc_size = manchester_sample_size(data_len);
+
+	if (sample_buf_len < enc_size)
+		return -EINVAL;
+
+	/* SOF */
+	*(mencs.samples16++) = MANCHESTER_SEQ_D;
+
+	for (i = 0; i < data_len; i++)
+		manchester_enc_byte(&mencs, data[i]);
+		
+	/* EOF */
+	*(mencs.samples16++) = MANCHESTER_SEQ_F;
+
+	return enc_size;
+}
+#endif
+#if 0
+/* Broken? */
+#define BPSK_SPEED_212	
+
+
+static u_int32_t bpsk_sample_size(u_int8_t frame_bytelen);
+
+int bpsk_encode(char *sample_buf, u_int16_t sample_buf_len,
+		const char *data, u_int8_t data_len)
+{
+	/* burst of 32 sub carrier cycles */	
+	memset(sample_buf, 0x55, 8);
+
+}
+#endif
-- 
cgit v1.2.3