From be06b92597a590e47dd05c52b99181976c5d3ccf Mon Sep 17 00:00:00 2001
From: Amr Bekhit <amr@helmpcb.com>
Date: Tue, 26 Nov 2019 17:36:21 +0300
Subject: [PATCH] Add support for the LimeSDR. Use "limesdr" for the --source
 flag.

---
 .gitignore       |  1 +
 apps/tpms_rx     |  4 +++-
 python/source.py | 38 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..d163863
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+build/
\ No newline at end of file
diff --git a/apps/tpms_rx b/apps/tpms_rx
index 7afad6a..a0326b3 100755
--- a/apps/tpms_rx
+++ b/apps/tpms_rx
@@ -38,7 +38,7 @@ import tpms
 
 from tpms.packet_check import packet_decode
 
-from tpms.source import source_hackrf, source_rtlsdr, source_file
+from tpms.source import source_hackrf, source_rtlsdr, source_limesdr, source_file
 from tpms.ask import ask_channel_filter
 from tpms.fsk import fsk_center_tracking, fsk_demodulator
 from tpms.decode import clock_recovery
@@ -226,6 +226,8 @@ class top_block(gr.top_block):
 			self.source = source_hackrf(args.tuned_frequency, args.if_rate)
 		elif source == 'rtlsdr':
 			self.source = source_rtlsdr(args.tuned_frequency, args.if_rate)
+		elif source == 'limesdr':
+			self.source = source_limesdr(args.tuned_frequency, args.if_rate)
 		elif source == 'file':
 			self.source = source_file(args.file)
 		else:
diff --git a/python/source.py b/python/source.py
index 561a32d..26e9d69 100644
--- a/python/source.py
+++ b/python/source.py
@@ -120,6 +120,44 @@ def __init__(self, target_frequency, if_sampling_rate):
 
 		self.connect(self.source, self.if_filter, self)
 
+class source_limesdr(gr.hier_block2):
+	def __init__(self, target_frequency, if_sampling_rate):
+		super(source_limesdr, self).__init__(
+			"source_limesdr",
+			gr.io_signature(0, 0, 0),
+			gr.io_signature(1, 1, gr.sizeof_gr_complex*1),
+		)
+
+		import limesdr
+
+		rf_sampling_rate = 10e6
+		baseband_bandwidth = 1750000
+		offset_frequency = 0
+
+		rf_gain = 30			# Gains set assuming a front-end filter keeps out-of-band noise down.
+
+		if_filter_attenuation = 60
+
+		rf_decimation, rf_decimation_remainder = divmod(rf_sampling_rate, if_sampling_rate)
+		if rf_decimation_remainder != 0:
+			raise RuntimeError('RF decimation must be an integer')
+		rf_decimation = int(round(rf_decimation))
+		tuning_frequency = target_frequency - offset_frequency
+
+		self.source = limesdr.source('', 0, '')
+		self.source.set_sample_rate(rf_sampling_rate)
+		self.source.set_center_freq(tuning_frequency, 0)
+		self.source.set_gain(rf_gain, 0)
+		self.source.set_antenna(2,0)
+		self.source.set_bandwidth(max(1.5e6, baseband_bandwidth), 0)
+		self.source.calibrate(max(2.5e6, rf_sampling_rate), 0)
+
+		if_taps = firdes.low_pass_2(1.0, rf_sampling_rate, if_sampling_rate*0.45, if_sampling_rate*0.1, if_filter_attenuation)
+		self.if_filter = filter.freq_xlating_fir_filter_ccc(rf_decimation, (if_taps), offset_frequency, rf_sampling_rate)
+		#self.if_filter.set_min_output_buffer(1048576)
+
+		self.connect(self.source, self.if_filter, self)
+
 class source_file(gr.hier_block2):
 	def __init__(self, file_path, throttle_rate=None):
 		super(source_file, self).__init__(