Renesas SH7781 用户手册

22.   Serial I/O with FIFO (SIOF) 

Rev.1.00  Jan. 10, 2008  Page 1144 of 1658 
REJ09B0261-0100 

 

The SIOF has one type of interrupt. 

Interrupts can be issued by several sources. Each source is shown as an SIOF status in SISTR. 
Table 22.14 lists the SIOF interrupt sources. 

Table 22.14  SIOF Interrupt Sources 

1 TDREQ 

Transmit 

FIFO 

transfer 

request 

The transmit FIFO stores data of 
specified size or more. 

2 

Transmission 

TFEMP 

Transmit FIFO empty 

The transmit FIFO is empty. 

3 

RDREQ 

Receive FIFO transfer 
request 

The receive FIFO stores data of 
specified size or more. 

4 

Reception 

RFFUL 

Receive FIFO full 

The receive FIFO is full. 

5 

TCRDY 

Transmit control data 
ready 

The transmit control register is ready to 
be written to. 

6 

Control 

RCRDY 

Receive control data 
ready 

The receive control data register stores 
valid data. 

7 Error 

TFUDF Transmit 

FIFO 

underflow 

Serial data transmit timing has arrived 
while the transmit FIFO is empty. 

8  

TFOVF Transmit 

FIFO 

overflow Write to the transmit FIFO is performed 

while the transmit FIFO is full. 

9 

 

RFOVF 

Receive FIFO overflow  Serial data is received while the receive 

FIFO is full. 

10  

RFUDF  Receive 

FIFO 

underflow 

The receive FIFO is read while the 
receive FIFO is empty. 

11  

FSERR  Frame 

Synchronous 

Error  

A synchronous signal is input before 
the specified bit number has been 
passed (in slave mode). 

12 

 

SAERR 

Slot assign error 

The same slot is specified in both serial 
data and control data. 

 

Whether an interrupt is issued or not as the result of an interrupt source is determined by the 
SIIER settings. If an interrupt source is set to 1 and the corresponding bit in SIIER is set to 1, an 
SIOF interrupt is issued.