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RA8900 SA / CE
1. Overview ................................................................................................................................................................................ 1
2. Block Diagram ........................................................................................................................................................................ 1
3. Terminal description ............................................................................................................................................................... 2
3.1. Terminal connections ............................................................................................................................................. 2
3.2. Pin Functions .......................................................................................................................................................... 2
4. Absolute Maximum Ratings ................................................................................................................................................... 3
5. Recommended Operating Conditions .................................................................................................................................... 3
6. Frequency Characteristics ..................................................................................................................................................... 3
7. Electrical Characteristics ........................................................................................................................................................ 4
7.1. DC Characteristics ................................................................................................................................................. 4
7.2. AC Characteristics .................................................................................................................................................. 5
8. Use Methods .......................................................................................................................................................................... 6
8.1. Description of Registers ......................................................................................................................................... 6
8.1.1. Write / Read and Bank Select ................................................................................................................ 6
8.1.2. Register table (Basic time and calendar register) ................................................................................... 6
8.1.3. Register table (Extension register) ......................................................................................................... 7
8.2. Details of Registers ................................................................................................................................................ 8
8.2.1. Clock counter (SEC - HOUR ) ................................................................................................................ 8
8.2.2. Calendar counter ( WEEK - YEAR ) ....................................................................................................... 9
8.2.3. Alarm registers ..................................................................................................................................... 10
8.2.4. Fixed-cycle timer control registers ........................................................................................................ 10
8.2.5. Extension register ................................................................................................................................. 10
8.2.6. Flag register .......................................................................................................................................... 11
8.2.7. Control register ..................................................................................................................................... 12
8.2.8. Temperature Data register ................................................................................................................... 14
8.2.9. Backup power supply function register ................................................................................................. 14
8.3. Fixed-cycle Timer Interrupt Function .................................................................................................................... 15
8.3.1. Diagram of fixed-cycle timer interrupt function ..................................................................................... 15
8.3.2. Related registers for function of time update interrupts. ....................................................................... 16
8.3.3. Fixed-cycle timer interrupt interval (example) ....................................................................................... 17
8.3.4. Fixed-cycle timer start timing ................................................................................................................ 17
8.4. Time Update Interrupt Function ............................................................................................................................ 18
8.4.1. Time update interrupt function diagram ................................................................................................ 18
8.4.2. Related registers for time update interrupt functions. ........................................................................... 19
8.5. Alarm Interrupt Function ....................................................................................................................................... 20
8.4.1. Diagram of alarm interrupt function ...................................................................................................... 20
8.5.2. Related registers .................................................................................................................................. 21
8.5.2. Examples of alarm settings .................................................................................................................. 22
8.6. About the interrupt function for operation /INT="L" interrupt output. ..................................................................... 23
8.7. Temperature compensation function. ................................................................................................................... 23
8.7.1. Temperature compensation function .................................................................................................... 23
8.7.2. Related registers for temperature compensation function .................................................................... 23
8.8. Battery backup switchover function ...................................................................................................................... 24
8.8.1. Description of Battery backup switchover function ............................................................................... 24
8.8.2. Control the contents of the power switching ......................................................................................... 25
8.8.3. Function that can be used in the backup state ..................................................................................... 25
8.8.4. Notes on power switching function is used ........................................................................................... 26
8.8.5. Related registers of the backup power supply switching function ........................................................ 26
8.9. Reading/Writing Data via the I 2 C Bus Interface ................................................................................................... 27
8.9.1. Overview of I 2 C-BUS ........................................................................................................................... 27
8.9.2. System configuration ............................................................................................................................ 27
8.9.4. Data transfers and acknowledge responses during I 2 C-BUS communications ................................... 29
8.9.5. Slave address ....................................................................................................................................... 29
2
8.10. Backup and Recovery ........................................................................................................................................ 31
8.11. About access at the time of backup return and Initial power supply .................................................................. 32
8.12. Flow chart ........................................................................................................................................................... 33
8.13. Connection with Typical Microcontroller ............................................................................................................. 36
8.14. When used as a clock source (32 kHz-TCXO) ................................................................................................... 36
9. External Dimensions/Marking Layout ................................................................................................................................. 37
10. Application notes ................................................................................................................................................................ 39
2
C bus communications .................................................................................... 28
C bus protocol .................................................................................................................................... 30
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