TPMS2 preset changed. Few CC1101 registers documented.

RogueMaster · Jan 9, 2023 · 4e36d03 · 4e36d03
1 parent 811d8f3
commit 4e36d03
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Showing 2 changed files with 46 additions and 6 deletions.
diff --git a/app_subghz.c b/app_subghz.c
@@ -13,8 +13,8 @@ ProtoViewModulation ProtoViewModulations[] = {
     {"2FSK 47.6Khz", FuriHalSubGhzPreset2FSKDev476Async, NULL},
     {"MSK", FuriHalSubGhzPresetMSK99_97KbAsync, NULL},
     {"GFSK", FuriHalSubGhzPresetGFSK9_99KbAsync, NULL},
-    {"TPMS FSK 28Khz", 0, (uint8_t*)protoview_subghz_tpms1_async_regs},
-    {"TPMS FSK 47Khz", 0, (uint8_t*)protoview_subghz_tpms2_async_regs},
+    {"TPMS 1 (FSK)", 0, (uint8_t*)protoview_subghz_tpms1_async_regs},
+    {"TPMS 2 (FSK)", 0, (uint8_t*)protoview_subghz_tpms2_async_regs},
     {NULL, 0, NULL} /* End of list sentinel. */
 };
 

diff --git a/custom_presets.h b/custom_presets.h
@@ -1,5 +1,45 @@
 #include <cc1101.h>
 
+/* This is how to configure registers MDMCFG3 and MDMCFG4.
+ *
+ * Data rate kBaud setting:
+ *
+ * MDMCFG3 is the data rate mantissa, the exponent is in MDMCFG4,
+ * last 4 bits of the register.
+ *
+ * The rate (assuming 26Mhz crystal) is calculated as follows:
+ *
+ * ((256+MDMCFG3)*(2^MDMCFG4:0..3bits)) / 2^28 * 26000000.
+ *
+ * For instance for the default values of MDMCFG3 (34) and MDMCFG4 (12):
+ *
+ * ((256+34)*(2^12))/(2^28)*26000000 = 115051.2688000000, that is 115KBaud
+ *
+ * Bandwidth filter setting:
+ *
+ * BW filter as just 16 possibilities depending on how the first nibble
+ * (first 4 bits) of the MDMCFG4 bits are set. Instead of providing the
+ * formula, it is simpler to show all the values of the nibble and the
+ * corresponding bandwidth filter.
+ *
+ * 0 812khz
+ * 1 650khz
+ * 2 541khz
+ * 3 464khz
+ * 4 406khz
+ * 5 325khz
+ * 6 270khz
+ * 7 232khz
+ * 8 203khz
+ * 9 162khz
+ * a 135khz
+ * b 116khz
+ * c 102khz
+ * d 82 khz
+ * e 68 khz
+ * f 58 khz
+ */
+
 /* 20 KBaud, 2FSK, 28.56 kHz deviation, 325 Khz bandwidth filter. */
 static uint8_t protoview_subghz_tpms1_async_regs[][2] = {
     /* GPIO GD0 */
@@ -45,7 +85,7 @@ static uint8_t protoview_subghz_tpms1_async_regs[][2] = {
     {0, 0},
 };
 
-/* 20 KBaud, 2FSK, 44.60 kHz deviation, 270 Khz bandwidth filter. */
+/* 40 KBaud, 2FSK, 19 kHz deviation, 102 Khz bandwidth filter. */
 static uint8_t protoview_subghz_tpms2_async_regs[][2] = {
     /* GPIO GD0 */
     {CC1101_IOCFG0, 0x0D}, // GD0 as async serial data output/input
@@ -61,9 +101,9 @@ static uint8_t protoview_subghz_tpms2_async_regs[][2] = {
     {CC1101_MDMCFG0, 0x00},
     {CC1101_MDMCFG1, 0x02},
     {CC1101_MDMCFG2, 0x04}, // Format 2-FSK/FM, No preamble/sync, Disable (current optimized). Other code reading TPMS uses GFSK, but should be the same when in RX mode.
-    {CC1101_MDMCFG3, 0x93}, // Data rate is 20kBaud
-    {CC1101_MDMCFG4, 0x67}, // Rx BW filter is 270.833333 kHz
-    {CC1101_DEVIATN, 0x47}, // Deviation 47.60742 kHz
+    {CC1101_MDMCFG3, 0x93}, // Data rate is 40kBaud
+    {CC1101_MDMCFG4, 0x6A}, // 6 = BW filter 270kHz, A = Data rate exp
+    {CC1101_DEVIATN, 0x41}, // Deviation 19.042 kHz
 
     /* Main Radio Control State Machine */
     {CC1101_MCSM0, 0x18}, // Autocalibrate on idle-to-rx/tx, PO_TIMEOUT is 64 cycles(149-155us)