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Rework I2C Parsing

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Fixes:
10bit I2C Parsing does not work  #86

* Comments for parsing/learning logic
* Changed segment value construction
* Added Address and operation to each segment
* Add 10 bit read detection
* Add Re-start / repeat start detection
This commit is contained in:
Shawn Ferry 2023-10-17 00:45:29 -04:00
parent f1f9aeb17a
commit 7d05c52627
No known key found for this signature in database
1 changed files with 84 additions and 7 deletions
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91
Software/LogicAnalyzer/I2CProtocolAnalyzer/I2CAnalyzer.cs
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@ -48,66 +48,143 @@ namespace I2CProtocolAnalyzer
int startPosition;
int endPosition;
string addr = "";
string op = "";
string addr_space = "";
byte value;
bool ack;
bool frameError;
bool foundStartStop;
bool repeatStart = false;
bool addressByte = true;
bool address10 = false;
bool address10read = false;
byte firstAddressByte = 0;
int pos = FindStartCondition(0, scl, sda, out startPosition, out endPosition);
if (pos == -1)
// If no start is found no further analysis
return new ProtocolAnalyzedChannel[0];
segments.Add(new ProtocolAnalyzerDataSegment { FirstSample = startPosition, LastSample = endPosition, Value = $"START" });
while (pos < sda.Samples.Length)
{
// iterate through samples byte by byte
pos = ReadByte(pos, scl, sda, out startPosition, out endPosition, out value, out ack, out frameError);
// no (more) bytes stop processing
if (pos == -1)
break;
// Create New Empty Segment
var segment = new ProtocolAnalyzerDataSegment { FirstSample = startPosition, LastSample = endPosition, Value = "" };
// convert byte value to printable ascii or '.'
string asciival = value >= 0x20 && value <= 0x7e ? Encoding.ASCII.GetString(new byte[] { (byte)value }) : "·";
var segment = new ProtocolAnalyzerDataSegment { FirstSample = startPosition, LastSample = endPosition, Value = $"0x{value.ToString("X2")} '{asciival}' <{(ack ? "A" : "N")}{(frameError ? "F" : "")}>" };
if (address10read)
{
address10read = false;
// Check for 10 bit high address pattern
// 0b11110NNN
if ((value & 0xf8) == 0xf0)
{
// current byte is firstAddressByte with read set
if ((firstAddressByte | 1) == value)
{
// Reset addressByte from repeat start
addressByte = false;
op = "Read";
segment.Value += "10b Op Change";
segment.Value += $"\r\nAddress: {addr}";
segment.Value += $" Op: {op}";
}
// else This is a new start with a new address
}
}
// Check/Parse address byte(s)
if (addressByte)
{
addressByte = false;
segment.Value += $"\r\nOp: {((value & 1) == 1 ? "Read" : "Write")}";
op = (value & 1) == 1 ? "Read" : "Write";
// Check 10bit High Byte address mask
// 0x11110NNN
if ((value & 0xf8) == 0xf0)
{
// Mark for 10 bit second byte address parsing
address10 = true;
firstAddressByte = value;
segment.Value += "10b High Addr Byte";
addr_space = "10b";
addr = $">= {((value & 6) >> 1) << 7}";
}
else
segment.Value += $"\r\nAddress (7b): 0x{(value >> 1).ToString("X2")}";
{
addr = $"0x{value >> 1:X2}";
addr_space = "7b";
// Add 7Bit Address to Segment
// Address (7b): 0x12
segment.Value += $"{addr_space} Address: {addr}";
}
// Add Operation to segment for address Byte
segment.Value += $"\r\nOp: {op}";
}
// Parse 10 bit low address byte
else if (address10)
{
address10 = false;
segment.Value += $"\r\nAddress (10b): {(((firstAddressByte & 6) << 7) | value).ToString("X4")}";
addr = $"0x{((firstAddressByte & 6) << 7) | value:X4}";
// Add 10 bit address to segment using high byte address bits and current byte value
// Address (10b): 0x031A
segment.Value += "10b Low Addr Byte";
segment.Value += $"\r\nAddress: {addr} Op: {op}";
// enable check for high address byte repeat with read bit
address10read = true;
}
if (segment.Value == "")
{
// Add Addr Data to Empty Segment
segment.Value += $"{addr_space} {addr}";
}
// Add Byte Data to Segment
// HEX_VALUE 'ASCII_VALUE' <A(CK)/N(ACK)/F(rame Error)>
// 0x3A ':' <A>
segment.Value += $"\r\n{op}: 0x{value.ToString("X2")} '{asciival}' <{(ack ? "A" : "N")}{(frameError ? "F" : "")}>";
// Add segment for processed byte
segments.Add(segment);
bool isStart;
// Search for next start
pos = FindStartStopCondition(pos, scl, sda, out isStart, out startPosition, out endPosition, out foundStartStop);
// no more start/stop processing complete
// TODO: REMOVE? this assumes capture ends with whole transaction?
if (pos == -1)
break;
if (foundStartStop)
segments.Add(new ProtocolAnalyzerDataSegment { FirstSample = startPosition, LastSample = endPosition, Value = isStart ? "START" : "STOP" });
{
string start_stop = (repeatStart && isStart) ? "RE-START" : (isStart ? "START" : "STOP");
// Add START/STOP segment
segments.Add(new ProtocolAnalyzerDataSegment { FirstSample = startPosition, LastSample = endPosition, Value = start_stop });
repeatStart = isStart;
addressByte = true;
}
// If last start/stop is not start look for following start
if (foundStartStop && !isStart)
{
pos = FindStartCondition(pos, scl, sda, out startPosition, out endPosition);
@ -117,13 +194,13 @@ namespace I2CProtocolAnalyzer
segments.Add(new ProtocolAnalyzerDataSegment { FirstSample = startPosition, LastSample = endPosition, Value = $"START" });
addressByte = true;
}
}
ProtocolAnalyzedChannel channel = new ProtocolAnalyzedChannel("SDA", sda.ChannelIndex, renderer, segments.ToArray(), Colors.White, Color.FromUInt32(0x7f008b8b));
return new ProtocolAnalyzedChannel[] { channel };
return new ProtocolAnalyzedChannel[] { channel
};
}
private int FindStartStopCondition(int pos, ProtocolAnalyzerSelectedChannel scl, ProtocolAnalyzerSelectedChannel sda, out bool isStart, out int startPosition, out int endPosition, out bool found)