i2c speed dropping down #1563
Comments
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@xiruilin What problems are you seeing? Error Messages? What is your Circuit? I need more Info before I can diagnose your problem. Chuck. |
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Error Messages: [E][esp32-hal-i2c.c:1113] i2cCheckLineState(): Bus Invalid State, TwoWire() Can't init [E][esp32-hal-i2c.c:1113] i2cCheckLineState(): Bus Invalid State, TwoWire() Can't init [E][esp32-hal-i2c.c:1113] i2cCheckLineState(): Bus Invalid State, TwoWire() Can't init [E][esp32-hal-i2c.c:1113] i2cCheckLineState(): Bus Invalid State, TwoWire() Can't init |
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@xiruilin ok,
This sequence of error messages is telling you:
The i2c hardware peripheral saw someone else using the bus, it waited 50ms, but the bus was never released.
You were sending a Write command equivalent to: Wire.beginTransmission(0x3e);
Wire.write(0x01);
Wire.write(0x02);
Wire.endTransmission(true);
This is the interrupt sequence received by the ISR handler: Then it received a second interrupt, the START at millisecond: 0x0000cfed: [02] 0x0001 0x0200 0x0000 0x0000 0x0000cfed Then the default 50ms timeout expired, and it exited with a Bus Busy error. It then tried to clear the bus by manually stimulating it:
but failed. the SDA gpio pin was held LOW and did not respond to the manual bus clearing cycle. This is the code from /cores/esp32/esp32-hal-i2c.c: static bool i2cCheckLineState(int8_t sda, int8_t scl){
if(sda < 0 || scl < 0){
return true;//return true since there is nothing to do
}
// if the bus is not 'clear' try the recommended recovery sequence, START, 9 Clocks, STOP
digitalWrite(sda, HIGH);
digitalWrite(scl, HIGH);
pinMode(sda, PULLUP|OPEN_DRAIN|OUTPUT|INPUT);
pinMode(scl, PULLUP|OPEN_DRAIN|OUTPUT|INPUT);
if(!digitalRead(sda) || !digitalRead(scl)) { // bus in busy state
log_w("invalid state sda=%d, scl=%d\n", digitalRead(sda), digitalRead(scl));
digitalWrite(sda, HIGH);
digitalWrite(scl, HIGH);
delayMicroseconds(5);
digitalWrite(sda, LOW);
for(uint8_t a=0; a<9; a++) {
delayMicroseconds(5);
digitalWrite(scl, LOW);
delayMicroseconds(5);
digitalWrite(scl, HIGH);
}
delayMicroseconds(5);
digitalWrite(sda, HIGH);
}
if(!digitalRead(sda) || !digitalRead(scl)) { // bus in busy state
log_e("Bus Invalid State, TwoWire() Can't init");
return false; // bus is busy
}
return true;
}These error message are telling me that you have a hardware fault, the SDA pin is LOW. Chuck. |
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Thanks @stickbreaker for your detailed answers. The same device，use old Wire library, it works good at 100kHz, Because our application needs to transmit a lot of data through i2c, so the speed of using 50kHz is much slower than that of 100kHz. May I trouble you to see if there is any solution? Thanks again! |
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@xiruilin what i2c device are you using? Chuck. |
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Fixed with #1767 =) |
My i2c device is support high speed to 1MHz, it works good in 100kHz.
When update to new Wire library, it only work down to 50kHz, Why?
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