SH7263 Datasheet, PDF (1111/1862 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7260 Series

20.8 Usage Notes
Section 20 IEBus^TM Controller (IEB)
20.8.1 Note on Operation when Transfer is Incomplete after Transfer of the Maximum
Number of Bytes
(1) 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 transmission has not been completed
because the message length value exceeds the maximum number of transfer bytes in one frame,
the IEB sets the error flag and enters a wait state. At this time, transfer proceeds until the (n + 1)th
byte has been transmitted, where n is the maximum number of transfer bytes. Then, when NAK is
received via the acknowledge bit of the (n + 1)th byte, the TXERO flag is set. If ACK is received
rather than NAK, the TXF flag is set.
Figure 20.18 shows the timing of operations when the maximum number of transfer bytes is
reached but transmission has not been completed.
IETSR
TXERO
Master
transmission
HD MA SA CT DL D1 D2
Dn-1 Dn Dn+1
When NAK is received for Dn + 1
When ACK is received for Dn + 1
TXF
[Legend]
HD: Header
MA: Master address field
SA: Slave address field
CT: Control field
DL: Message length field
Dn: Data field (n = Maximum number of transfer bytes)
Figure 20.18 Timing of Operations when Transmission Has Not Been Completed
Within the Maximum Number of Transfer Bytes
Rev. 2.00 Mar. 14, 2008 Page 1077 of 1824
REJ09B0290-0200