r5f21346mnfp Renesas Electronics Corporation., r5f21346mnfp Datasheet - Page 754

• Manufacturer Part Number: r5f21346mnfp
• Description: Single-chip Mcus Incorporates The R8c Cpu Core
• Manufacturer: Renesas Electronics Corporation.

R8C/34M Group
R01UH0131EJ0100 Rev.1.00
Jun 21, 2011
35.10.3 Time Reading Procedure of Real-Time Clock Mode
In real-time clock mode, read registers TRESEC, TREMIN, TREHR, and TREWK when time data is updated
and read the PM bit in the TRECR1 register when the BSY bit is set to 0 (not while data is updated).
Also, when reading several registers, an incorrect time will be read if data is updated before another register is
read after reading any register.
In order to prevent this, use the reading procedure shown below.
•
•
•
(1) Monitor the BSY bit.
(2) Monitor until the BSY bit is set to 0 after the BSY bit is set to 1 (approximately 62.5 ms while the BSY bit
(3) Read necessary contents of registers TRESEC, TREMIN, TREHR, and TREWK and the PM bit in the
•
(1) Read necessary contents of registers TRESEC, TREMIN, TREHR, and TREWK and the PM bit in the
(2) Read the same register as (1) and compare the contents.
(3) Recognize as the correct value if the contents match. If the contents do not match, repeat until the read
Using an interrupt
Read necessary contents of registers TRESEC, TREMIN, TREHR, and TREWK and the PM bit in the
TRECR1 register in the timer RE interrupt routine.
Monitoring with a program 1
Monitor the IR bit in the TREIC register with a program and read necessary contents of registers TRESEC,
TREMIN, TREHR, and TREWK and the PM bit in the TRECR1 register after the IR bit in the TREIC register
is set to 1 (timer RE interrupt request generated).
Monitoring with a program 2
Using read results if they are the same value twice
Also, when reading several registers, read them as continuously as possible.
is set to 1).
TRECR1 register after the BSY bit is set to 0.
TRECR1 register.
contents match with the previous contents.
35. Usage Notes
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