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authorhenryk <henryk@6dc7ffe9-61d6-0310-9af1-9938baff3ed1>2007-11-26 06:20:17 +0000
committerhenryk <henryk@6dc7ffe9-61d6-0310-9af1-9938baff3ed1>2007-11-26 06:20:17 +0000
commit16d42d5f6b8df076a04a18ffd13d0defc999c7bf (patch)
tree5ea288cc5c509bdc549690877a68bb03679cb447 /openpicc/application/iso14443_layer3a.h
parent29ea5bbf5b9c3b3679aa40e4ee7029284cb424c6 (diff)
Prepare transmission code
Restructure/add some buffer code Reset the watchdog timer (now at 1.5s), add a watchdog pinger thread git-svn-id: https://svn.openpcd.org:2342/trunk@352 6dc7ffe9-61d6-0310-9af1-9938baff3ed1
Diffstat (limited to 'openpicc/application/iso14443_layer3a.h')
-rw-r--r--openpicc/application/iso14443_layer3a.h53
1 files changed, 52 insertions, 1 deletions
diff --git a/openpicc/application/iso14443_layer3a.h b/openpicc/application/iso14443_layer3a.h
index 6f32dd5..142128e 100644
--- a/openpicc/application/iso14443_layer3a.h
+++ b/openpicc/application/iso14443_layer3a.h
@@ -15,6 +15,7 @@ enum ISO14443_STATES {
ERROR, /* Some unrecoverable error has occured */
};
+/******************** RX ************************************/
/* standard derived magic values */
#define ISO14443A_FDT_SHORT_1 1236
#define ISO14443A_FDT_SHORT_0 1172
@@ -30,6 +31,15 @@ enum ISO14443_STATES {
#define ISO14443A_SOF_LEN 4
/* Length in samples of a short frame */
#define ISO14443A_SHORT_LEN 32
+/* This is wrong: a short frame is 1 start bit, 7 data bits, 1 stop bit
+ * followed by no modulation for one bit period. The start bit is 'eaten' in
+ * SSC Compare 0, but the remaining 7+1+1 bit durations must be sampled and
+ * compared. At four times oversampling this would be 9*4=36 samples, which is
+ * more than one SSC transfer. You'd have to use two transfers of 18 samples
+ * each and modify the comparison code accordingly.
+ * Since four times oversampling doesn't work reliably anyway (every second
+ * sample is near an edge and might sample 0 or 1) this doesn't matter for now.*/
+#error Four times oversampling is broken, see comments in code
#else
/* definitions for two-times oversampling */
@@ -38,8 +48,49 @@ enum ISO14443_STATES {
#define ISO14443A_SOF_SAMPLE 0x01
#define ISO14443A_SOF_LEN 2
-#define ISO14443A_SHORT_LEN 16
+#define ISO14443A_SHORT_LEN 18
#endif
+/* A short frame should be received in one single SSC transfer */
+#if (ISO14443A_SHORT_LEN <= 8)
+/* SSC transfer size in bits */
+#define ISO14443A_SHORT_TRANSFER_SIZE 8
+#define ISO14443A_SHORT_TYPE u_int8_t
+
+#elif (ISO14443A_SHORT_LEN <= 16)
+#define ISO14443A_SHORT_TRANSFER_SIZE 16
+#define ISO14443A_SHORT_TYPE u_int16_t
+
+#elif (ISO14443A_SHORT_LEN <= 32)
+#define ISO14443A_SHORT_TRANSFER_SIZE 32
+#define ISO14443A_SHORT_TYPE u_int32_t
+
+#else
+#error ISO14443A_SHORT_LEN defined too big
+#endif
+
+/******************** TX ************************************/
+/* in bytes, not counting parity */
+#define MAXIMUM_FRAME_SIZE 256
+
+typedef struct {
+ enum { TYPE_A, TYPE_B } type;
+ union {
+ struct {
+ enum { SHORT_FRAME, STANDARD_FRAME, AC_FRAME } format;
+ enum { PARITY, /* Calculate parity on the fly, ignore the parity field below */
+ GIVEN_PARITY, /* Use the parity bits from the parity field below */
+ NO_PARITY, /* Don't send any parity */
+ } parity;
+ } a;
+ } parameters;
+ u_int32_t numbytes;
+ u_int8_t numbits, bit_offset;
+ u_int8_t data[MAXIMUM_FRAME_SIZE];
+ u_int8_t parity[MAXIMUM_FRAME_SIZE]; /* Only the LSB of each byte is used */
+} iso14443_frame;
+
+extern const iso14443_frame ATQA_FRAME;
+
#endif /*ISO14443_LAYER3A_H_*/
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