M16C6NK Datasheet, PDF (198/404 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

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M16C/6N Group (M16C/6NK, M16C/6NM)
15. Serial Interface
15.1.3.1 Detection of Start and Stop Condition
Whether a start or a stop condition has been detected is determined.
A start condition-detected interrupt request is generated when the SDAi pin changes state from high to
low while the SCLi pin is in the high state. A stop condition-detected interrupt request is generated when
the SDAi pin changes state from low to high while the SCLi pin is in the high state.
Figure 15.25 shows the detection of start and stop condition.
Because the start and stop condition-detected interrupts share the interrupt control register and vector,
check the BBS bit in the UiSMR register to determine which interrupt source is requesting the interrupt.
3 to 6 cycles < duration for setting-up ⁽¹⁾
3 to 6 cycles < duration for holding ⁽¹⁾
Duration for
setting-up
SCLi
SDAi
(Start condition)
SDA i
(Stop condition)
Duration for
holding
i = 0 to 2
NOTE:
1.When the PCLK1 bit in the PCLKR register = 1, this is the cycle number
of f1SIO, and when the PCLK1 bit = 0, this is the cycle number of f2SIO.
Figure 15.25 Detection of Start and Stop Condition
15.1.3.2 Output of Start and Stop Condition
A start condition is generated by setting the STAREQ bit in the UiSMR4 register (i = 0 to 2) to “1” (start).
A restart condition is generated by setting the RSTAREQ bit in the UiSMR4 register to “1” (start).
A stop condition is generated by setting the STPREQ bit in the UiSMR4 register to “1” (start).
The output procedure is described below.
(1) Set the STAREQ bit, RSTAREQ bit or STPREQ bit to “1” (start).
(2) Set the STSPSEL bit in the UiSMR4 register to “1” (output).
Table 15.13 and Figure 15.26 show the functions of the STSPSEL bit.
Rev.2.00 Nov 28, 2005 page 180 of 378
REJ09B0124-0200