diff options
| -rw-r--r-- | decoders/caliper/__init__.py | 16 | ||||
| -rw-r--r-- | decoders/caliper/pd.py | 69 |
2 files changed, 41 insertions, 44 deletions
diff --git a/decoders/caliper/__init__.py b/decoders/caliper/__init__.py index 3fc99fe..44dab08 100644 --- a/decoders/caliper/__init__.py +++ b/decoders/caliper/__init__.py @@ -18,17 +18,17 @@ ## ''' -This decodes digital output of cheap generic calipers (usualy made in china) -Decoder will show measured value in milimeters or inches. +This decoder interprets the digital output of cheap generic calipers +(usually made in China), and shows the measured value in millimeters +or inches. -Please note that these devices often communicate on low voltage level, -which might not be possible to capture with 3.3V logic analyzers. -So additional circuitry might be needed to capture the signal. +Notice that these devices often communicate on voltage levels below +3.3V and may require additional circuitry to capture the signal. -This is NOT for calipers using Digimatic protocol (eg. Mitutoyo and similar brands) - -More info: +This decoder does not work for calipers using the Digimatic protocol +(eg. Mitutoyo and similar brands). +For more information see: http://www.shumatech.com/support/chinese_scales.htm https://www.instructables.com/id/Reading-Digital-Callipers-with-an-Arduino-USB/ ''' diff --git a/decoders/caliper/pd.py b/decoders/caliper/pd.py index 3db0473..cbb01cf 100644 --- a/decoders/caliper/pd.py +++ b/decoders/caliper/pd.py @@ -28,23 +28,26 @@ class Decoder(srd.Decoder): id = 'caliper' name = 'Caliper' longname = 'Digital calipers' - desc = 'Protocol of cheap generic digital calipers' + desc = 'Protocol of cheap generic digital calipers.' license = 'mit' inputs = ['logic'] outputs = [] channels = ( - {'id': 'clk', 'name': 'CLK', 'desc': 'Serial clock line'}, - {'id': 'data', 'name': 'DATA', 'desc': 'Serial data line'}, + {'id': 'clk', 'name': 'CLK', 'desc': 'Serial clock line'}, + {'id': 'data', 'name': 'DATA', 'desc': 'Serial data line'}, ) options = ( - {'id': 'timeout_ms', 'desc': 'Timeout packet after X ms, 0 to disable', 'default': 10}, - {'id': 'unit', 'desc': 'Convert units', 'default': 'keep', 'values': ('keep', 'mm', 'inch')}, - {'id': 'changes', 'desc': 'Changes only', 'default': 'no', 'values': ('no', 'yes')}, + {'id': 'timeout_ms', 'desc': 'Packet timeout in ms, 0 to disable', + 'default': 10}, + {'id': 'unit', 'desc': 'Convert units', 'default': 'keep', + 'values': ('keep', 'mm', 'inch')}, + {'id': 'changes', 'desc': 'Changes only', 'default': 'no', + 'values': ('no', 'yes')}, ) - tags = ['Analog/digital', 'IC', 'Sensor'] + tags = ['Analog/digital', 'Sensor'] annotations = ( - ('measurements', 'Measurements'), - ('warning', 'Warnings'), + ('measurement', 'Measurement'), + ('warning', 'Warning'), ) annotation_rows = ( ('measurements', 'Measurements', (0,)), @@ -70,84 +73,78 @@ class Decoder(srd.Decoder): def start(self): self.out_ann = self.register(srd.OUTPUT_ANN) - #Switch bit order of variable x, which is l bit long - def bitr(self,x,l): + # Switch bit order of variable x, which is l bit long. + def bitr(self, x, l): return int(bin(x)[2:].zfill(l)[::-1], 2) def decode(self): self.last_measurement = None while True: - clk, data = self.wait([{0: 'r'},{'skip': round(self.samplerate/1000)}]) - #print([clk,data]) + clk, data = self.wait([{0: 'r'}, {'skip': round(self.samplerate / 1000)}]) - #Timeout after inactivity - if(self.options['timeout_ms'] > 0): - if self.samplenum > self.es_cmd + (self.samplerate/(1000/self.options['timeout_ms'])): + # Timeout after inactivity. + if self.options['timeout_ms'] > 0: + if self.samplenum > self.es_cmd + (self.samplerate / (1000 / self.options['timeout_ms'])): if self.bits > 0: - self.put(self.ss_cmd, self.samplenum, self.out_ann, [1, ['timeout with %s bits in buffer'%(self.bits),'timeout']]) + self.put(self.ss_cmd, self.samplenum, self.out_ann, [1, ['timeout with %s bits in buffer' % (self.bits), 'timeout']]) self.reset() - #Do nothing if there was timeout without rising clock edge + # Do nothing if there was timeout without rising clock edge. if self.matched == (False, True): continue - #Store position of last activity + # Store position of last activity. self.es_cmd = self.samplenum - #Store position of first bit + # Store position of first bit. if self.ss_cmd == 0: self.ss_cmd = self.samplenum - #Shift in measured number + # Shift in measured number. if self.bits < 16: self.number = (self.number << 1) | (data & 0b1) - self.bits+=1 + self.bits += 1 continue - #Shift in flag bits + # Shift in flag bits. if self.bits < 24: self.flags = (self.flags << 1) | (data & 0b1) - self.bits+=1 + self.bits += 1 if self.bits < 24: continue - #Hooray! We got last bit of data + # We got last bit of data. self.es_cmd = self.samplenum - #Do actual decoding - - #print(format(self.flags, '08b')); + # Do actual decoding. negative = ((self.flags & 0b00001000) >> 3) inch = (self.flags & 0b00000001) number = self.bitr(self.number, 16) - #print(format(number, '016b')) - if negative > 0: number = -number inchmm = 25.4 #how many mms in inch if inch: - number = number/2000 + number = number / 2000 if self.options['unit'] == 'mm': number *= inchmm inch = 0 else: - number = number/100 + number = number / 100 if self.options['unit'] == 'inch': - number = round(number/inchmm,4) + number = round(number / inchmm, 4) inch = 1 units = "in" if inch else "mm" - measurement = (str(number)+units) - #print(measurement) + measurement = (str(number) + units) if ((self.options['changes'] == 'no') or (self.last_measurement != measurement)): self.put(self.ss_cmd, self.es_cmd, self.out_ann, [0, [measurement, str(number)]]) self.last_measurement = measurement - #Prepare for next packet + # Prepare for next packet. self.reset() |