Infineon SPI F-RAM FM33256B, Manual

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Application Note Please read the Important Notice and Warnings at the end of this document 001-87564 Rev.*D
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AN408
r e s t r i c t e d
A Design Guide to SPI F- RAM™ Processor
Companion - FM33256B
About this document
Scope and purpose
AN408 provides an overview and design guidelines for the SPI F-RAM real-time clock (RTC) Processor
Companion part - FM33256B. This document also includes a typical application and an example code. For
information on the basic SPI operation, refer to the application note
AN304 - SPI Guide for F-RAM.
Intended audience
It is intended for the users of SPI F-RAM TM processor companion FM33256B.
Table of contents
About this document ....................................................................................................................... 1
Table of contents ............................................................................................................................ 1
1 Introduction .......................................................................................................................... 2
2 Two Logical Devices in One ...................................................................................................... 3
3 Typical Application ................................................................................................................. 4
4 Processor Companion Features ............................................................................................... 5
4.1 System Power-On Reset with RST pin .................................................................................................... 5
4.2 Early Power-Fail Warning ........................................................................................................................ 6
4.3 Event Counter .......................................................................................................................................... 6
4.4 Serial Number .......................................................................................................................................... 7
5 Real-Time Clock ..................................................................................................................... 8
5.1 Backup Power .......................................................................................................................................... 9
5.2 RTC Calibration........................................................................................................................................ 9
5.2.1 Setup Example ................................................................................................................................... 9
6 Power Cycle Considerations ................................................................................................... 10
7 Summary ............................................................................................................................. 11
8 Related Application Notes ...................................................................................................... 11
9 PSoC 3 User Module ............................................................................................................... 11
10 Pseudo Code Examples .......................................................................................................... 12
10.1 Enable RTC Oscillator ............................................................................................................................ 12
10.2 Set RTC Time/Date ................................................................................................................................ 13
10.3 Set VTP Voltage Detect Trip Point ......................................................................................................... 14
10.4 Read RTC Registers ................................................................................................................................ 14
10.5 Read Event Counters ............................................................................................................................. 15
10.6 SPI Processor Companion Write ........................................................................................................... 16
10.7 SPI Processor Companion Read ........................................................................................................... 17
Revision history............................................................................................................................. 18