PCF2127 View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'PCF2127' PDF : 101 Pages View PDF
NXP Semiconductors
PCF2127
Accurate RTC with integrated quartz crystal for industrial applications
9. Interfaces
The PCF2127 has an I2C-bus or SPI-bus interface using the same pins. The selection is
done using the interface selection pin IFS (see Table 85).
Table 85. Interface selection input pin IFS
Pin Connection
Bus interface
IFS
VSS
BBS
SPI-bus
I2C-bus
Reference
Section 9.1
Section 9.2
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To select the SPI-bus interface, pin IFS has to be
connected to pin VSS.
a. SPI-bus interface selection
Fig 35. Interface selection
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To select the I2C-bus interface, pin IFS has to be
connected to pin BBS.
b. I2C-bus interface selection
9.1 SPI-bus interface
Data transfer to and from the device is made by a 3 line SPI-bus (see Table 86). The data
lines for input and output are split. The data input and output line can be connected
together to facilitate a bidirectional data bus (see Figure 36). The SPI-bus is initialized
whenever the chip enable line pin SDA/CE is inactive.
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Fig 36. SDI, SDO configurations
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PCF2127
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 8 — 19 December 2014
© NXP Semiconductors N.V. 2014. All rights reserved.
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