Datasheet

78K0/Kx2-L CHAPTER 10 REAL-TIME COUNTER
R01UH0028EJ0400 Rev.4.00 387
Sep 27, 2010
Yes
RTCE = 1
RWAIT = 1
No
Yes
RWAIT = 0
No
RWST = 1 ?
RWST = 0 ?
STOP mode
RTCE = 1
STOP mode
Waiting at least for 2
f
SUB clocks
Sets to counter operation
start
Shifts to STOP mode
Sets to counter operation
start
Sets to stop the SEC to YEAR
counters, reads the counter
value, write mode
Checks the counter wait status
Sets the counter operation
Shifts to STOP mode
Example 2
Example 1
10.4.2 Shifting to STOP mode after starting operation
Perform one of the following processing when shifting to STOP mode immediately after setting RTCE to 1.
However, after setting RTCE to 1, this processing is not required when shifting to STOP mode after the first INTRTC
interrupt has occurred.
• Shifting to STOP mode when at least two subsystem clocks (f
SUB) (about 62 μ s) have elapsed after setting RTCE to 1
(see Figure 10-20, Example 1).
• Checking by polling RWST to become 1, after setting RTCE to 1 and then setting RWAIT to 1. Afterward, setting
RWAIT to 0 and shifting to STOP mode after checking again by polling that RWST has become 0 (see Figure 10-20,
Example 2).
Figure 10-20. Procedure for Shifting to STOP Mode After Setting RTCE to 1