M16C30P_07 Datasheet, PDF (168/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
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.
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⁾
SCLi
SDAi
(Start condition)
SDA i
(Stop condition)
Duration for
setting up
Duration for
holding
i = 0 to 2
NOTES :
1. When the PCLK1 bit in the PCLKR register = 1, this is the cycle number of
f1SIO, and the PCLK1 bit = 0, this is the cycle number of f2SIO.
Figure 15.26 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).
The function of the STSPSEL bit is shown in Table 15.14 and Figure 15.27.
Rev.1.22 Mar 29, 2007 Page 152 of 291
REJ09B0179-0122