Cypress CY14B101P manual Read RTC Rdrtc Instruction, Burst Mode Read Instruction Timing

Page 11

PRELIMINARYCY14B101P

Figure 11. Burst Mode Read Instruction Timing

CS

SCK

SI

SO

0

1

 

2

3

4

5

6

7

0

1

2

3

4

5

6

7

 

20

21

22

23

0

1

2

3

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5

6

7

0

 

7

0

1

2

3

4

5

6

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

~~

 

 

 

 

 

 

 

 

 

 

 

 

~

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

~

 

 

 

 

 

 

 

 

 

 

 

Op-Code

 

 

 

 

 

 

 

 

 

 

17-bit Address

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

0

 

0

0

1

1

0

0

0

0

0

0

0

A16

 

A3

A2

A1

A0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MSB

 

 

 

 

 

~~

 

 

LSB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Byte 1

 

 

 

 

 

 

 

Data Byte N

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D7

D6 D5 D4

D3 D2

D1 D0

D7 D0

D7

D6

D5 D4

D3 D2

D1 D0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MSB

 

 

 

 

LSB

~~

MSB

 

 

 

 

LSB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CS

SCK

SI

SO

Figure 12. Write Instruction Timing

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

20

21

22

23

0

1

2

3

4

5

6

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

~~

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Op-Code

 

 

 

 

 

 

 

 

 

17-bit Address

 

 

 

 

 

 

 

 

 

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

A16

A3

A2

A1

A0

D7

D6

D5

D4

D3

D2

D1

D0

 

 

 

 

 

 

 

 

MSB

 

 

 

 

 

 

~ ~

 

 

 

LSB MSB

 

 

Data

 

 

LSB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HI-Z

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 13. Burst Mode Write Instruction Timing

CS

SCK

SI

SO

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

20

21

22

23

0

1

2

3

4

5

6

7

0

 

7

0

1

2

3

4

5

6

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

~~

 

 

 

 

 

 

 

 

 

 

 

~

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Byte 1

 

 

 

~

 

 

Data Byte N

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Op-Code

 

 

 

 

 

 

 

 

 

 

17-bit Address

 

 

 

 

 

 

 

 

~~

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

~ ~

 

 

 

 

D6 D5 D4

 

 

 

 

 

 

D6 D5

D4

 

 

 

 

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

A16

A3

A2

A1 A0

D7

D3 D2

D1

D0 D7

D0

D7

D3 D2

D1

D0

 

 

 

 

 

 

 

 

MSB

 

 

 

 

 

 

 

 

 

 

LSB MSB

 

 

 

 

 

LSB

 

 

 

 

 

 

 

 

 

 

HI-Z

READ RTC (RDRTC) Instruction

Read RTC (RDRTC) instruction allows the user to read the contents of RTC registers. Reading the RTC registers through the serial output (SO) pin requires the following sequence: After the CS line is pulled LOW to select a device, the RDRTC opcode is transmitted through the SI line followed by eight address bits for selecting the register. Any data on the SI line after the address bits is ignored. The data (D7-D0) at the specified address is then shifted out onto the SO line. RDRTC also allows burst mode read operation. When reading multiple bytes from RTC registers, the address rolls over to 0x00 after the last RTC register address (0x0F) is reached.

The R bit in RTC Flag register must be set to '1' before reading RTC time keeping registers to avoid reading transitional data. Modifying the RTC Flag registers requires a Write RTC cycle. The R bit must be cleared to '0' after completion of the read operation.

The easiest way to read RTC registers is to perform RDRTC in burst mode. The read may start from the first RTC register (0x00) and the CS must be held LOW to allow the data from all 16 RTC registers to be transmitted through the SO pin.

Note Read RTC instruction operates at a maximum clock frequency of 25 MHz.

Document #: 001-44109 Rev. *B

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Contents Sram Array FeaturesLogic Block Diagram OverviewHold PinoutsPin Definitions Pin Name Type Description Store Operation Device OperationSram Write Sram ReadSerial Peripheral Interface SPI Master Commonly used terms used in SPI protocol are given belowSPI Modes System Configuration Using SPI nvSRAMSPI Functional Description SPI Operating FeaturesWrite Status Register Wrsr Instruction Status RegisterRead Status Register Rdsr Instruction Block Protection Write Enable Wren InstructionWrite Disable Wrdi Instruction Write Protection and Block ProtectionWpen WEN Memory AccessRead Sequence Read Write Sequence WriteRead RTC Rdrtc Instruction Burst Mode Read Instruction TimingSoftware Store Store AutoStore DisableNvSRAM Special Instructions Write RTC Wrtc InstructionHold Pin Operation AutoStore Disable AsdisbAutoStore Enable Asenb Software Recall RecallReal Time Clock Operation Calibrating the Clock AlarmWatchdog Timer Flags Register Power MonitorInterrupt Register InterruptsRTC Recommended Component Configuration Accessing the Real Time Clock through SPIWDF Oscf RTC Register Map1 BCD Format Data Function/RangeOscen Register Map Detail Alarm DayAlarm Hours Alarm MinutesWDF Oscf CAL Register Map Detail Alarm SecondsTime Keeping Centuries Flags 0x00Parameter Description Test Conditions Min Max Unit DC Electrical CharacteristicsMaximum Ratings Operating RangeAC Test Conditions Data Retention and EnduranceCapacitance Thermal ResistanceAC Switching Characteristics ~ ~ ~ ~ Parameters Description CY14B101P Unit Min Max AutoStore or Power Up RecallSwitching Waveforms CY14B101P Hardware Store Pulse Width To Output Active Time when write latch not setHardware Store Cycle Parameter DescriptionCY 14 B 101 P SF X C T Ordering Code Package Diagram Package Type Operating RangeOrdering Information Part Numbering NomenclaturePin 300 mil Soic Package Package DiagramsSubmission Orig. Description of Change Date Document HistoryREV ECN no USB Sales, Solutions, and Legal InformationWorldwide Sales and Design Support Products PSoC Solutions