Add support for bitrate

[chevdor]

The hardware we talk about here does not really need a high bitrate and 50k (default) is usually enough. However, when used in combination with a display for instance, using the another bitrate becomes interesting. Currently, the bitrate seem to be unexposed/ignored and the default value of 50k is always taken.

I would be good to be able to pass the bitrate as well as in:
var matrix = new Matrix8x8(I2C1, { scl: 5, sda: 4, address: 0x77, brightness: 15, bitrate: 100e3 })

[chalkers]

Hi @chevdor

Can you explain what does the bitrate does? And show an example or two?

[chevdor]

@chalkers the bitrate defines how fast the data is transferred.
A higher bitrate allows ultimately a higher refresh rate. Higher rates are of course more tricky to reach depending on the electronic you have. On the other hand, the ability to LOWER the bitrate can also be nice for challenging environment where it matters more to get the data than how fast it comes.

Raising up the bitrate, I could reach a 'paint' in ~71ms on a SH1106. That´s around 14 fps.

I gave an example with the Matrix8x8 which may not be the best. The issue currently with i2c is that your program will HANG if you don´t get and acknowledge. So lowering the bitrate may help in some case as well.