code is the discovery scanner with their specific I2S stuff etc commented out
i have a tmp102 and a 128×64 0.98 I2C oled SSD1306, with 4k7 pullups and 3v3 plugged in
this is SERIALINTERFACE #defined as SerialUSB
...
0 Unknown error at address 0x3B
0 I2C device found at address 0x3C !
0 Unknown error at address 0x3D
...
...
0 Unknown error at address 0x47
0 I2C device found at address 0x48 !
0 Unknown error at address 0x49
...
0 Unknown error at address 0x7E
0 ok
1 timeout
4 default for other
code is the discovery scanner with their specific I2S stuff etc commented out
i have a tmp102 and a 128×64 0.98 I2C oled SSD1306, with 4k7 pullups and 3v3 plugged in
this is SERIALINTERFACE #defined as SerialUSB
...
0 Unknown error at address 0x3B
0 I2C device found at address 0x3C !
0 Unknown error at address 0x3D
...
...
0 Unknown error at address 0x47
0 I2C device found at address 0x48 !
0 Unknown error at address 0x49
...
0 Unknown error at address 0x7E
“Unknown error at address 0x..” when there is no device responding.
stephen
stephen
The STM32GENERIC example is originally from this Arduino site and is modified for the STM.
Hmm .. the I2C address field is 7 bits witch gives use 128 addresses. I know, not all are usable.
0 Unknown error at address 0x47
Probably the I2C driver is working different compared to the Arduino-Uno implementation and returns different status messages ?
istr trying 3 or 4 before finding one that worked at all on STM, even then it wasn’t both hard and soft i2c.
btw that’s a get out for not remembering which
there seem to be 3 responses from the HAL routine
0. ok – definitely a device present
4. nothing there
1. timeout – but what then, something possibly there
i can understand reporting the first and last, but why report nothing?
stephen
Returns
byte, which indicates the status of the transmission:
0:success
1:data too long to fit in transmit buffer
2:received NACK on transmit of address
3:received NACK on transmit of data
4:other error
So we should probably alter the text message ( into “other error” ) in the I2C scanner program.
// --------------------------------------
// i2c_scanner
..
#include <Wire.h>
TwoWire Wire2(I2C2, PB11, PB10);
#define Wire Wire2
#define Serial SerialUART1
void setup()
..
else if (error==4)
{
//Serial.print("Unknow error at address 0x");
//if (address<16)
// Serial.print("0");
//Serial.println(address,HEX);
}
}
..
The issue is following:
How to build a demo, reading time off DS3231/2, when using I2C2 (not the default I2C1).
When playing with simple stuff like above, no prob, but this is a chicken-egg-situation (or Catch22 one)..
TwoWire Wire2(I2C2, pina, pinb); creates a new instance Wire2 on the second I2C controller.
Tried with #define Wire2 Wire, but after a hundred various combinations I still get an error with Wire redefinition..
But how to organize the code such it compiles with the DS3232RTC library????
PS: with I2C1 and with the default Wire it compiles fine.. (except you have to adjust for our __STM32F4__ and add the _BV macro definition)..
22:24:50
28/4/2017
22:24:51
28/4/2017
Wire.stm32SetInstance(I2Cx);
Wire.stm32SetSDA(sda);
Wire.stm32SetSCL(scl);
rtc....()
...
FYI – an enhanced I2C library which supports master/slave in immediate/interrupt/dma mode – for Teensy CM4 however.. https://github.com/nox771/i2c_t3
How can I use 2 I2C interfaces?
E.g. F7 Disco has an internal I2C bus for the touch which is use in the form
Wire.stm32SetInstance(I2C3);
Wire.stm32SetSDA(PH8);
Wire.stm32SetSCL(PH7);
Wire.begin();
TwoWire Wire2(I2C2, sda2, scl2); // check chip documentation and board schematic
TwoWire Wire3(I2C3, sda3, scl3); // check chip documentation and board schematic
TwoWire Wire4(I2C4, sda4, scl4); // check chip documentation and board schematic
i suspect they’ll have completely separate i2c structures.
for us, why not do it in same way as multiple spi usage.
stephen
“Problem is every library is written with the assumption that there is only one I2C, and it is called Wire.
Disclaimer: I actually not tried to use multiple at once.”
For me it seems quite clear on how to handle it: On boards which have a Arduino compatible connector the I2C which is connected to this connector shall have the name “Wire”.
The names of the others shall be based on the interface number.
E.g.
Wire1
Wire2 ==> Wire on this exampel board
Wire3
I’m trying to use this functionality on an F0, and it seems that on address match SCK is held low indefinitely. Is this the intended behaviour, and if so is there something I should be doing in a callback to release the bus?
Simple example with nothing more than initializing the Wire library as an I2C slave shows this behaviour for me:
#include "Wire.h"
void setup() {
Wire.begin(30);
}
void loop() { }
void receive(int bytes) {
// Received bytes
}
void request() {
uint8_t response[1] = {9};
Wire.write(response, sizeof(response)); // responding
}
void setup() {
Wire.onReceive(receive);
Wire.onRequest(request);
Wire.begin(30);
}
With changes(26 Sep) to Wire.cpp it won’t compile I2C examples for any board (except F0 probably):
https://github.com/danieleff/STM32GENER … ire.cpp#L7
You cannot check #ifndef I2C1_EV_IRQn, because I2C1_EV_IRQn is enum not #define.
The same for #ifndef I2C2_EV_IRQn.
Maybe change it to:
#if defined(STM32F0)
#define I2C1_EV_IRQn I2C1_IRQn
#define I2C2_EV_IRQn I2C1_IRQn
#endif
Wire.begin(); is default 100Khz, I want 400Khz?
Wire.begin();
Wire.setClock(400000);
Problem was, that in the docs there is SetClock() , not setClock()
scroll down a bit
stephen
