22. Serial I/O with FIFO (SIOF)
Rev.1.00 Jan. 10, 2008 Page 1145 of 1658
REJ09B0261-0100
(2) Regarding Transmit and Receive Classification
The transmit sources and receive sources are signals indicating the state; after being set, if the state
changes, they are automatically cleared by the SIOF.
When the DMA transfer is used, a DMA transfer request is pulled low for one cycle at the end of
DMA transfer.
(3) Processing when Errors Occur
On occurrence of each of the errors indicated as a status in SISTR, the SIOF performs the
following operations.
Transmit FIFO underflow (TFUDF)
The immediately preceding transmit data is again transmitted.
Transmit FIFO overflow (TFOVF)
The contents of the transmit FIFO are protected, and the write operation causing the overflow
is ignored.
Receive FIFO overflow (RFOVF)
Data causing the overflow is discarded and lost.
Receive FIFO underflow (RFUDF)
An undefined value is output on the bus.
Frame synchronization error (FSERR)
The internal counter is reset according to the signal in which an error occurs.
Slot assign error (SAERR)
If the same slot is assigned to both serial data and control data, the slot is assigned to serial
data.
If the same slot is assigned to two control data items, the data cannot be transferred
correctly.