Re: I2C, what does "clocked out" mean?

Question

I'm not trained in EE.

I'm programming a master-receiver device which controls a MAX11644/MAX11645. The datasheet explains the read cycle, saying:

A read cycle must be initiated to obtain conversion results. Read cycles begin with the bus master issuing a START condition followed by seven address bits and a read bit (R/W = 1). If the address byte is successfully received, the MAX11644/MAX11645 (slave) issues an acknowledge. The master then reads from the slave. The result is transmitted in 2 bytes; first 4 bits of the first byte are high, then MSB through LSB are consecutively clocked out.

All of this I understand, except the very last part: "MSB through LSB are consecutively clocked out". Most significant bit? Isn't this the first bit? We already know the first bit in the first byte is hi. And what does "clocked out" mean?

Answer 1

Most significant bit? Isn't this the first bit?

It may or may not be. There's no unambiguous definition of "first". RS232, for example, outputs the least significant bit first. If you mean the one that happens to be output first, then yes, that's what the next part is saying.

We already know the first bit in the first byte is hi.

Right. But the device outputs it anyway.

And what does "clocked out" mean?

It means that they are produced as output on consecutive clock cycles. That is, each time the clock advances, the next bit (in the order defined there) is placed on the output pin.