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?
what's shift clock
Started by ●December 28, 2008
Reply by ●December 28, 20082008-12-28
leilei wrote:> 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
Reply by ●December 30, 20082008-12-30
On Dec 28, 4:05=A0am, leilei <huxuelei...@gmail.com> wrote:> hi, when i read rtl8139 driver's source, there's a macro like this: > #define EE_SHIFT_CLK =A0 =A00x04 =A0 =A0/* 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?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
Reply by ●December 30, 20082008-12-30
On Dec 28, 6:05=A0am, leilei <huxuelei...@gmail.com> wrote:> hi, when i read rtl8139 driver's source, there's a macro like this: > #define EE_SHIFT_CLK =A0 =A00x04 =A0 =A0/* 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?Look up "synchronous serial". I wouldn't be surprised if Wikipedia has a decent entry. JM
Reply by ●December 30, 20082008-12-30
On Dec 28, 2:18 pm, Thad Smith <ThadSm...@acm.org> wrote:> leilei wrote: > > 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? > > -- > ThadYou are correct, Thad. Very obvious from just a quick glance at the code. AL
Reply by ●December 31, 20082008-12-31
LittleAlex wrote:> On Dec 28, 2:18 pm, Thad Smith <ThadSm...@acm.org> wrote: >> leilei wrote: >>> 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 > > You are correct, Thad. > > Very obvious from just a quick glance at the code.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.
Reply by ●January 1, 20092009-01-01
On 31/12/2008 Anthony Fremont wrote:> LittleAlex wrote: > >On Dec 28, 2:18 pm, Thad Smith <ThadSm...@acm.org> wrote: > > > leilei wrote: > > > > 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 > > > > You are correct, Thad. > > > > Very obvious from just a quick glance at the code. > > 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
