9-22 Intel® PXA26x Processor Family Developer’s Manual
Inter-Integrated Circuit Bus Interface Unit
13. Read IDBR data.
14. Initiate STOP abort condition (STOP with no data transfer).
Set ICR[MA]
Note: If a NAK is not sent i n step 11, the next transaction must involve another data byte read.
9.7 Glitch Suppression Logic
The I2C unit has built-in glitch suppression logic that suppresses glitches of 60ns or less. This is
within the 50ns glitch suppression specification.
9.8 Reset Conditions
Software must ensure that the I2C unit is not busy before it asserts a res et. Software must also
ensure that the I2C bus is idle when the unit is enabled after reset. When directed to r e set, the I2C
unit, except for ISAR, returns to the default reset condition. ISAR is not affected by a reset.
When the ICR[UR] bit is set, the I2C unit resets but the associated I2C MMRs remain intact. When
resetting the I2C unit with the ICR’s unit reset, use the following guidelines:
1. Set the reset bit in the ICR register and clear the remainder of the register.
2. Clear the ISR register.
3. Clear reset in the ICR.
9.9 Register Definitions
The registers in Table 9- 8 are associated with the I2C unit and are located in the processor
peripheral memory-mapped address space.

9.9.1 I2C Bus Monitor Register- IBMR

The I2C Bus Monitor Register (IBMR) tracks the status of the SCL and SDA pins. The va lues of
these pins are recorded in this read-only IBMR so sof twar e can determin e wh en the I2C bu s is h ung
and the I2C unit must be reset.
Table 9-8. I2C Register Definitions
Register Addresses Name Section
0x4030 1680 IBMR Section9.9.1, “I2C Bus Monitor Register- IBMR”
0x4030 1688 IDBR Section 9.9.2, “I2C Data Buffer Register- IDBR”
0x4030 1690 ICR Section9.9.3, “I2C Control Register- ICR”
0x4030 1698 ISR Section9.9.4, “I2C Status Register”
0x4030 16A0 ISAR Section 9.9.5, “I2C Slave Address Register- ISAR”