diff options
Diffstat (limited to 'decoders/spi')
| -rw-r--r-- | decoders/spi/pd.py | 42 |
1 files changed, 24 insertions, 18 deletions
diff --git a/decoders/spi/pd.py b/decoders/spi/pd.py index 1252a6a..aec1fac 100644 --- a/decoders/spi/pd.py +++ b/decoders/spi/pd.py @@ -125,7 +125,6 @@ class Decoder(srd.Decoder): def __init__(self): self.samplerate = None - self.oldclk = 1 self.bitcount = 0 self.misodata = self.mosidata = 0 self.misobits = [] @@ -136,7 +135,6 @@ class Decoder(srd.Decoder): self.samplenum = -1 self.ss_transfer = -1 self.cs_was_deasserted = False - self.oldcs = None self.have_cs = self.have_miso = self.have_mosi = None def metadata(self, key, value): @@ -263,12 +261,12 @@ class Decoder(srd.Decoder): self.reset_decoder_state() - def find_clk_edge(self, miso, mosi, clk, cs): - if self.have_cs and self.oldcs != cs: + def find_clk_edge(self, miso, mosi, clk, cs, first): + if self.have_cs and (first or self.matched[self.have_cs]): # Send all CS# pin value changes. + oldcs = None if first else 1 - cs self.put(self.samplenum, self.samplenum, self.out_python, - ['CS-CHANGE', self.oldcs, cs]) - self.oldcs = cs + ['CS-CHANGE', oldcs, cs]) if self.cs_asserted(cs): self.ss_transfer = self.samplenum @@ -286,11 +284,9 @@ class Decoder(srd.Decoder): return # Ignore sample if the clock pin hasn't changed. - if clk == self.oldclk: + if first or not self.matched[0]: return - self.oldclk = clk - # Sample data on rising/falling clock edge (depends on mode). mode = spi_mode[self.options['cpol'], self.options['cpha']] if mode == 0 and clk == 0: # Sample on rising clock edge @@ -309,27 +305,37 @@ class Decoder(srd.Decoder): if not self.samplerate: raise SamplerateError('Cannot decode without samplerate.') - # Either MISO or MOSI can be omitted (but not both). CS# is optional. + # The CLK input is mandatory. Other signals are (individually) + # optional. Yet either MISO or MOSI (or both) must be provided. + # Tell stacked decoders when we don't have a CS# signal. + if not self.has_channel(0): + raise ChannelError('Either MISO or MOSI (or both) pins required.') self.have_miso = self.has_channel(1) self.have_mosi = self.has_channel(2) - self.have_cs = self.has_channel(3) if not self.have_miso and not self.have_mosi: raise ChannelError('Either MISO or MOSI (or both) pins required.') - - # Tell stacked decoders that we don't have a CS# signal. + self.have_cs = self.has_channel(3) if not self.have_cs: self.put(0, 0, self.out_python, ['CS-CHANGE', None, None]) + # We want all CLK changes. We want all CS changes if CS is used. + # Map 'have_cs' from boolean to an integer index. This simplifies + # evaluation in other locations. + wait_cond = [{0: 'e'}] + if self.have_cs: + self.have_cs = len(wait_cond) + wait_cond.append({3: 'e'}) + # "Pixel compatibility" with the v2 implementation. Grab and # process the very first sample before checking for edges. The - # previous implementation did this by seeding old values with None, - # which led to an immediate "change" in comparison. + # previous implementation did this by seeding old values with + # None, which led to an immediate "change" in comparison. pins = self.wait({}) (clk, miso, mosi, cs) = pins - self.find_clk_edge(miso, mosi, clk, cs) + self.find_clk_edge(miso, mosi, clk, cs, True) while True: # Ignore identical samples early on (for performance reasons). - pins = self.wait([{0: 'e'}, {1: 'e'}, {2: 'e'}, {3: 'e'}]) + pins = self.wait(wait_cond) (clk, miso, mosi, cs) = pins - self.find_clk_edge(miso, mosi, clk, cs) + self.find_clk_edge(miso, mosi, clk, cs, False) |