Hi All,
SPI is more simplistic in internal IC hardware design than I2c. If the SPI data bus receive garbage (spikes or noise) you can pull the chip select high and start clocking the data in/out again.
SPI has /CS chip select Clock Data out Data in
I2C has Clock Data
Question ======== If an I2C bus receives garbage, how does one tell a I2C receiver to "reset" and start again, as there is only a clock and data line.
Thanks in Advance.
Joe
SPI
high
"reset"
By generating a premature stop condition.
Meindert
Meindert Sprang schrieb:
...and if one of the devices eventually blocks the bus with SDA=low (this can happen when a read access is aborted), apply SCL pulses until SDA goes high.
Tilmann
The correct way to RESET the I2C buss, is to do a repeat-START, then a STOP.
Works every time.
don
don schrieb:
Please note that you simply can't apply a (repeated) start condition when a device continuously holds SDA low. In such cases, you first have to provide SCL pulses until SDA gets high again, then do start-stop.
Tilmann
_If_ it lets go at all. I've seen cases where it didn't and a power cycle was required :-(
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Especially if the slave device is doing a clock stretch, holding SCL low.
--
Paul Carpenter | paul@pcserviceselectronics.co.uk
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Sort of the eternal stretch :-)
I like SPI a lot more although I2C does have the advantage of being able to hang it all onto the same serial bus. But that can at the same time cause hang-ups while SPI never hung on me.
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Paul Carpenter schrieb:
STOP.
I have always carefully selected only such I2C slaves that don't do clock stretching... :-)
Tilmann
Thanks all for your comments.
Joe
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