30.4.5.4 Exit from low-power/stop modes
The slave receive input detect circuit and address matching feature are still active on low
power modes (wait and stop). An asynchronous input matching slave address or general
call address brings the CPU out of low power/stop mode if the interrupt is not masked.
Therefore, TCF and IAAS both can trigger this interrupt.
30.4.5.5 Arbitration lost interrupt
The I2C is a true multimaster bus that allows more than one master to be connected on it.
If two or more masters try to control the bus at the same time, the relative priority of the
contending masters is determined by a data arbitration procedure. The I2C module asserts
the arbitration-lost interrupt when it loses the data arbitration process and the ARBL bit
in the Status Register is set.
Arbitration is lost in the following circumstances:
1. SDA is sampled as low when the master drives high during an address or data
transmit cycle.
2. SDA is sampled as low when the master drives high during the acknowledge bit of a
data receive cycle.
3. A START cycle is attempted when the bus is busy.
4. A repeated START cycle is requested in slave mode.
5. A STOP condition is detected when the master did not request it.
The ARBL bit must be cleared (by software) by writing 1 to it.
30.4.6 Programmable input glitch filter
An I2C glitch filter has been added outside legacy I2C modules but within the I2C
package. This filter can absorb glitches on the I2C clock and data lines for the I2C
module. The width of the glitch to absorb can be specified in terms of the number of
(half) bus clock cycles. A single Programmable Input Glitch Filter control register is
provided. Effectively, any down-up-down or up-down-up transition on the data line that
occurs within the number of clock cycles programmed in this register is ignored by the
I2C module. The programmer must specify the size of the glitch (in terms of bus clock
cycles) for the filter to absorb and not pass.
Chapter 30 Inter-Integrated Circuit (I2C)
KL02 Sub-Family Reference Manual, Rev. 2.1, July 2013
Freescale Semiconductor, Inc.
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