From 95097f3108033f69c19a315a7d042383b7295628 Mon Sep 17 00:00:00 2001 From: Uwe Hermann Date: Sun, 8 Sep 2013 15:16:11 +0200 Subject: [PATCH] i2c: Fix corner-case that can occur with LA triggers. Until now the I2C PD was basically ignoring the very first sample, and using that as the initial 'oldscl'/'oldsda' value. However, if your logic analyzers trigger on, say, SDA=low that will result in a file where the first sample is really important since it is the one which the PD will need to know that there's a falling edge on SDA. Thus, assume both SCL and SDA are high/1 when the PD starts. This is a good assumption since both pins have pullups on them in practice and are thus high/1 when the bus is idle. Later on we might want to have config options to let the PD assume other states of SDA/SCL initially. --- decoders/i2c/pd.py | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/decoders/i2c/pd.py b/decoders/i2c/pd.py index 0b85c66..c2eb524 100644 --- a/decoders/i2c/pd.py +++ b/decoders/i2c/pd.py @@ -86,9 +86,9 @@ class Decoder(srd.Decoder): self.wr = -1 self.is_repeat_start = 0 self.state = 'FIND START' - self.oldscl = None - self.oldsda = None - self.oldpins = None + self.oldscl = 1 + self.oldsda = 1 + self.oldpins = (1, 1) def start(self, metadata): self.out_proto = self.add(srd.OUTPUT_PROTO, 'i2c') @@ -206,12 +206,6 @@ class Decoder(srd.Decoder): continue self.oldpins, (scl, sda) = pins, pins - # First sample: Save SCL/SDA value. - if self.oldscl == None: - self.oldscl = scl - self.oldsda = sda - continue - # TODO: Wait until the bus is idle (SDA = SCL = 1) first? # State machine. -- 2.30.2