FM33256B
Document Number: 001-86213 Rev. *C
Page 3 of 39
Contents
Pinout ................................................................................ 4
Pin Definitions .................................................................. 4
Overview ............................................................................ 5
Memory Architecture ................................................... 5
Processor Companion ..................................................... 5
Processor Supervisor .................................................. 5
Manual Reset .............................................................. 6
Reset Flags ................................................................. 6
Power Fail Comparator ............................................... 6
Event Counter ............................................................. 7
Serial Number ............................................................. 7
Alarm ........................................................................... 8
Real-time Clock Operation ............................................... 8
Backup Power ............................................................. 9
Trickle Charger .......................................................... 10
Calibration ................................................................. 10
Crystal Type .............................................................. 10
Layout Recommendations ............................................. 10
Register Map ................................................................... 13
Serial Peripheral Interface – SPI Bus ............................ 23
SPI Overview ............................................................. 23
SPI Modes ................................................................. 24
Power Up to First Access .......................................... 25
Command Structure .................................................. 25
WREN - Set Write Enable Latch ............................... 25
WRDI - Reset Write Enable Latch ............................. 25
Status Register and Write Protection ........................... 26
RDSR - Read Status Register ................................... 26
WRSR - Write Status Register .................................. 26
RDPC - Read Processor Companion ........................ 27
WRPC - Write Processor Companion ....................... 27
Memory Operation .......................................................... 28
Write Operation ......................................................... 28
Read Operation ......................................................... 28
Maximum Ratings ........................................................... 30
Operating Range ............................................................. 30
DC Electrical Characteristics ........................................ 30
Data Retention and Endurance ..................................... 32
Capacitance .................................................................... 32
Thermal Resistance ........................................................ 32
AC Test Conditions ........................................................ 32
Supervisor Timing .......................................................... 33
AC Switching Characteristics ....................................... 34
Ordering Information ...................................................... 35
Ordering Code Definitions ......................................... 35
Package Diagram ............................................................ 36
Acronyms ........................................................................ 37
Document Conventions ................................................. 37
Units of Measure ....................................................... 37
Document History Page ................................................. 38
Sales, Solutions, and Legal Information ...................... 39
Worldwide Sales and Design Support ....................... 39
Products .................................................................... 39
PSoC® Solutions ...................................................... 39
Cypress Developer Community ................................. 39
Technical Support ..................................................... 39
