Table of Contents
Advertisement
Functional description
21.5.6.1 Byte transfer interrupt
The Transfer Complete Flag (TCF) bit is set at the falling edge of the ninth clock to
indicate the completion of a byte and acknowledgement transfer. When FACK is enabled,
TCF is then set at the falling edge of eighth clock to indicate the completion of byte.
21.5.6.2 Address detect interrupt
When the calling address matches the programmed slave address (I2C Address Register)
or when the GCAEN bit is set and a general call is received, the IAAS bit in the Status
Register is set. The CPU is interrupted, provided the IICIE bit is set. The CPU must
check the SRW bit and set its Tx mode accordingly.
21.5.6.3 Stop Detect Interrupt
2
When the stop status is detected on the I
C bus, the STOPF bit is set to 1. The CPU is
interrupted, provided the IICIE and SSIE bits are both set to 1.
21.5.6.4 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.
21.5.6.5 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.
MC9S08SU16 Reference Manual, Rev. 5, 4/2017
388
NXP Semiconductors
Advertisement
Table of Contents
