CY14B101P(2011) Ver la hoja de datos (PDF) - Cypress Semiconductor

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CY14B101P
(Rev.:2011)

1-Mbit (128 K × 8) Automotive Serial (SPI) nvSRAM with Real Time Clock

Cypress Semiconductor 

PRELIMINARY

CY14B101P

Accessing the Real Time Clock through SPI

CY14B101P uses 16 registers for RTC. These registers can be

read out or written to by accessing all 16 registers in burst mode

or accessing each register, one at a time. The RDRTC and

WRTC instructions are used to access the RTC.

All the RTC registers can be read in burst mode by issuing the

RDRTC instruction and reading all 16 bytes without bringing the

CS pin HIGH. The ‘R’ bit must be set while reading the RTC

timekeeping registers to ensure that transitional values of time

are not read.

Writes to the RTC register are performed using the WRTC

instruction. Writing RTC timekeeping registers and control

registers, except for the flag register needs the ‘W’ bit of the flag

register to be set to ‘1’. The internal counters are updated with

the new date and time setting when the ‘W’ bit is cleared to ‘0’.

All the RTC registers can also be written in burst mode using the

WRTC instruction.

Figure 20. RTC Recommended Component Configuration

C1

Y1

C2

Xout

Xin

Recommended Values

Y1 = 32.768 KHz (12.5 pF)

C1 = 10 pF

C2 = 67 pF

Note: The recommended values for C1 and C2 include

board trace capacitance.

Watchdog

Timer

Power

Monitor

VINT

Clock

Alarm

WDF

WIE

PF

PFE

AF

AIE

Figure 21. Interrupt Block Diagram

P/L

VCC

Pin

Driver

INT

H/L

VSS

WDF - Watchdog Timer Flag

WIE - Watchdog Interrupt

Enable

PF - Power Fail Flag

PFE - Power Fail Enable

AF - Alarm Flag

AIE - Alarm Interrupt Enable

P/L - Pulse/Level

H/L - High/Low

Document #: 001-61932 Rev. *B

Page 18 of 35

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