Datasheet

Chapter 10 Inter-Integrated Circuit (IICV2)
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor 317
10.5 Resets
The reset state of each individual bit is listed in Section 10.3, “Memory Map and Register Definition,”
which details the registers and their bit-fields.
10.6 Interrupts
IICV2 uses only one interrupt vector.
Table 10-9. Interrupt Summary
Internally there are three types of interrupts in IIC. The interrupt service routine can determine the interrupt
type by reading the status register.
IIC Interrupt can be generated on
1. Arbitration lost condition (IBAL bit set)
2. Byte transfer condition (TCF bit set)
3. Address detect condition (IAAS bit set)
The IIC interrupt is enabled by the IBIE bit in the IIC control register. It must be cleared by writing 0 to
the IBF bit in the interrupt service routine.
10.7 Initialization/Application Information
10.7.1 IIC Programming Examples
10.7.1.1 Initialization Sequence
Reset will put the IIC bus control register to its default status. Before the interface can be used to transfer
serial data, an initialization procedure must be carried out, as follows:
1. Update the frequency divider register (IBFD) and select the required division ratio to obtain SCL
frequency from system clock.
2. Update the IIC bus address register (IBAD) to define its slave address.
3. Set the IBEN bit of the IIC bus control register (IBCR) to enable the IIC interface system.
4. Modify the bits of the IIC bus control register (IBCR) to select master/slave mode, transmit/receive
mode and interrupt enable or not.
Interrupt Offset Vector Priority Source Description
IIC
Interrupt
— — — IBAL, TCF, IAAS
bits in IBSR
register
When either of IBAL, TCF or IAAS bits is set
may cause an interrupt based on arbitration
lost, transfer complete or address detect
conditions