HD64F7144F50V Datasheet, PDF (570/932 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

14. I²C Bus Interface (IIC) Option
14.4.8 DTC Operation
This LSI provides the DTC to allow continuous data transfer. The DTC is initiated when the IRTR
flag is set to 1, which is one of the two interrupt flags (IRIC and IRTR). When the ACKE bit is 0,
the ICDRE, IRIC, and IRTR flags are set at the end of data transmission regardless of the
acknowledge bit value. When the ACKE bit is 1, the ICDRE, IRIC, and IRTR flags are set if data
transmission is completed with the acknowledge bit value of 0, or only the IRIC flag is set if data
transmission is completed with the acknowledge bit value of 1.
When initiated, DTC transfers specified number of bytes, clears the ICDRE, IRIC, and IRTR flags
to 0. Therefore, no interrupt is generated during continuous data transfer; however, if data
transmission is completed with the acknowledge bit value of 1 when the ACKE bit is 1, DTC is
not initiated, thus allowing an interrupt to be generated if enabled.
The acknowledge bit may indicate specific events such as completion of receive processing for
some receiving device, and for other receiving device, the acknowledge bit may be held to 1,
indicating no specific event.
In the I²C bus format, since the slave device or the direction of transfer is selected by the slave
address or the R/W bit, and the acknowledge bit may indicate the end of reception or reception of
the final frame, the continuous transfer of data by the DTC must be combined with interrupt-
driven processing by the CPU.
Table 14.7 shows examples of processes in which the DTC is used. For the slave-mode processes,
it is assumed that the amount of data to be transferred is defined in advance.
Rev.4.00 Mar. 27, 2008 Page 524 of 882
REJ09B0108-0400