hi, when i read rtl8139 driver's source, there's a macro like this: #define EE_SHIFT_CLK 0x04 /* EEPROM shift clock. */ the comment say it is a eeprom shift clock. can any one tell me what is shift clock.and what it is used to do?
My first thought is that it is an I/O port bit mask for a clock line for an interface to a serial EEPROM. How is it used?
-- Thad
Hi Serial EEPROMs have no normal clock reference. They have a serial data in, shift clock and data out. The shift clock is used to shift the serial bits in and out. One would provide a bit on the serial in and then toggle the shift clock. One could then look at the serial out bit or repeat. Look at one of the specs for a serial EEPROM. Dwight
Look up "synchronous serial". I wouldn't be surprised if Wikipedia has a decent entry.
JM
You are correct, Thad.
Very obvious from just a quick glance at the code.
AL
I gave the OP basically the same answer two weeks ago (16 Dec) and even explained the code segment they posted that clocks out the data one bit at a time. I then advised them to look at SPI communications. It appears that the OP only cares to worry about this problem once per week.
I guess it takes him that long to read the next page of the data sheet.
-- John B
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