Pico: How to change the I2C timeout when using a i2c id scanner?

[espruino-discuss]

Posted at 2018-01-12 by @MaBecker

When testing this i2c scanner I figured out that there is a delay of 2sec before next scan.
A full scan over the 120 id will take about 240 seconds.

Is there a option to change this delay/timeout?

function getSSMS() {
  return [Date().getSeconds(),Date().getMilliseconds()].join(':');
}

function isDeviceOnBus(i2c,id) {
      console.log(getSSMS(),id);
      try {
        return i2c.readFrom(id,1);
      }
      catch(err) {
        return -1;
      }
}

function detect(i2c,first, last) {
      first = first | 0;
      last = last | 0x77;
      var idsOnBus = Array();
      for (var id = first; id <= last; id++) {
        if ( isDeviceOnBus(i2c,id) != -1) {
          idsOnBus.push(id);
        }
      }
      return idsOnBus;
}

SCL = B6; SDA = B7;  // PICO
I2C1.setup({sda:SDA,scl:SCL});

setTimeout(function(){
  console.log('I2C detect as array:',detect(I2C1));
},1000);

// output
53:67 0
55:67 1
57:69 2
59:70 3
1:71 4
3:71 5
5:71 6
7:70 7
9:68 8
11:64 9
......

[espruino-discuss]

Posted at 2018-01-12 by @gfwilliams

I'm afraid not. It might make more sense to implement the I2C scanner purely in JavaScript - all you need to do is clock out maybe 10 bits per device?

Just to add, software I2C (var i2c=new I2C();i2c.setup(...)) might be faster...

---

Posted at 2018-01-12 by @MaBecker

Wow - Now it is fast as expected!

SDA = B7; SCL = B6;               // Pico
i2c = new I2C();
i2c.setup({sda:SDA,scl:SCL});

Now a i2c.readFrom(0,1) returns a new Uint8Array([255]) shouldn't this throw an exception?

How to decide if this id is attached or not?

---

Posted at 2018-01-12 by @MaBecker

This was the change for the ESP8266: "i2c replace jsError() with jsExceptionHere() #868"

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Posted at 2018-01-15 by @gfwilliams

Software I2C applies across all boards, including ESP8266 - so you should see the same behaviour there if using software I2C.

It's odd, because there are definitely timeout checks in the I2c implementation