SH7261 Datasheet, PDF (973/1348 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7260 Series

20.8 Usage Notes
Section 20 IEBus^TM Controller (IEB) [R5S72612] [R5S72613]
20.8.1 Notes when the Communications have not been Completed within the Maximum
Number of Transmit Bytes
(1) Data Transmission
During the data transmission, when the maximum number of bytes defined by the communications
mode have been transmitted because a NAK has been received from the receive unit, or when
transmission has not been completed within the maximum number of transmit bytes because the
message length value exceeds it, the IEB sets the error flag of IETSR and enters the wait state. In
this case, the IEB transmits data for the maximum number of transmit bytes + one byte. Then, if a
NAK has been received in an acknowledge bit of data for the maximum number of transmit bytes
+ one byte, the TXERO flag is set. If an ACK is received, the TXF flag is set.
Figure 20.18 shows the operation timing when the transmission has not been completed within the
maximum number of transmit bytes.
IETSR
TXER0
IETSR
TXF
HD: Header
MA: Master address field
SA: Slave address field
CT: Control field
DL: Message length field
Dn: Data field (n = Max. no. of transfer bytes)
Master transmission
HD MA SA CT DL D1 D2
Dn-1 Dn Dn+1
NAK is received in Dn + 1
ACK is received in Dn + 1
Figure 20.18 Operation Timing when Transmission has not been Completed within
Maximum Number of Transmit Bytes
(2) Data Reception
During the data reception, when reception has not been completed within the maximum number of
bytes defined by the communications mode because of a parity error or overrun error causing the
retransfer of data, or when reception has not been completed because the message length value
exceeds the maximum number of receive bytes, the IEB sets the error flag of IERSR and enters
Rev. 2.00 Sep. 07, 2007 Page 941 of 1312
REJ09B0320-0200