SCL, SDA
external signals
DFF
Noise
suppress
circuits
SCL, SDA
internal signals
DFF
DFF
DFF
Figure 30-28. Programmable input glitch filter diagram
30.4.7 Address matching wakeup
When a primary, range, or general call address match occurs when the I2C module is in
slave receive mode, the MCU wakes from a low power mode where no peripheral bus is
running. Data sent on the bus that is the same as a target device address might also wake
the target MCU.
After the address matching IAAS bit is set, an interrupt is sent at the end of address
matching to wake the core. The IAAS bit must be cleared after the clock recovery.
NOTE
After the system recovers and is in Run mode, restart the I2C
module if it is needed to transfer packets. The SCL line is not
held low until the I2C module resets after address matching.
The main purpose of this feature is to wake the MCU from a
low power mode where no peripheral bus is running. When the
MCU is in such a mode: addressing as a slave, slave read/write,
and sending an acknowledge bit are not fully supported. To
avoid I2C transfer problems resulting from this situation,
firmware should prevent the MCU execution of a STOP
instruction when the I2C module is in the middle of a transfer
unless the Stop mode holdoff feature is used during this period
(set FLT[SHEN] to 1).
30.5 Initialization/application information
Module Initialization (Slave)
1. Write: Control Register 2
• to enable or disable general call
• to select 10-bit or 7-bit addressing mode
Initialization/application information
KL02 Sub-Family Reference Manual, Rev. 2.1, July 2013
492
Freescale Semiconductor, Inc.