SH7710 Datasheet, PDF (625/996 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series

Section 16 Serial Communication Interface with FIFO (SCIF)
Table 16.6 The SCIF Interrupt Sources
Interrupt
Source
Description
DMAC
Activation
Priority on Reset
Release
ERI
Interrupt initiated by receive error (ER) Not possible
High
RXI
Interrupt initiated by receive FIFO data Possible
full (RDF) or data ready (DR)*
BRI
Interrupt initiated by break (BRK) or Not possible
overrun error (ORER)
TXI
Interrupt initiated by transmit FIFO Possible
data empty (TDFE)
Low
Note: * The RXI by the DR is enabled only in asynchronous mode.
See section 4, Exception Handling, for priorities and the relationship with non-the SCIF
interrupts.
16.6 Usage Notes
Note the following when using the SCIF.
SCFTDR Writing and TDFE Flag: The TDFE flag in SCFSR is set when the number of
transmit data bytes written in SCFTDR has fallen to or below the transmit trigger number set by
bits TTRG1 and TTRG0 in SCFCR. After the TDFE flag is set, transmit data up to the number of
empty bytes in SCFTDR can be written, allowing efficient continuous transmission.
However, if the number of data bytes written in SCFTDR is equal to or less than the transmit
trigger number, the TDFE flag will be set to 1 again after being read as 1 and cleared to 0. TDFE
clearing should therefore be carried out when SCFTDR contains more than the transmit trigger
number of transmit data bytes.
The number of transmit data bytes in SCFTDR can be found from bits 12 to 8 in SCFDR.
SCFRDR Reading and RDF Flag: The RDF flag in SCFSR is set when the number of receive
data bytes in SCFRDR has become equal to or greater than the receive trigger number set by bits
RTRG1 and RTRG0 in SCFCR. After the RDF flag is set, receive data equivalent to the trigger
number can be read from SCFRDR, allowing efficient continuous reception.
However, if the number of data bytes in SCFRDR is still equal to or greater than the trigger
number after a read, the RDF flag will be set to 1 again if it is cleared to 0. The RDF flag should
therefore be cleared to 0 after being read as 1 after all receive data has been read.
The number of receive data bytes in SCFRDR can be found from bits 4 to 0 in SCFDR.
Rev. 2.00 Dec. 07, 2005 Page 583 of 950
REJ09B0079-0200