FM31274-G Ramtron, FM31274-G Datasheet - Page 11

• Manufacturer Part Number: FM31274-G
• Description: FRAM, MPU SUPPORT, 16K, RTC, SOIC14
• Manufacturer: Ramtron

Specifications of FM31274-G

• Memory Size: 16Kbit
• Nvram Features: RTC
• Supply Voltage Range: 4V To 5.5V
• Memory Case Style: SOIC
• No. Of Pins: 14
• Operating Temperature Range: -40°C To +85°C
• Interface: Serial
• Package / Case: SOIC
• Memory Configuration: 2048 X 8
• Interface Type: I2C, Serial, 2-Wire
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Register Map
The RTC and processor companion functions are accessed via 25 special function registers mapped to a separate 2-
wire device ID. The interface protocol is described below. The registers contain timekeeping data, control bits, or
information flags. A description of each register follows the summary table below.
Register Map Summary Table
Nonvolatile =
Note: When the device is first powered up and programmed, all registers must be written because the battery-
backed register values cannot be guaranteed. The table below shows the default values of the non-volatile
registers. All other register values should be treated as unknown.
Rev. 2.0
Jan. 2011
Address
0Eh
0Dh
0Ch
0Bh
0Ah
18h
17h
16h
15h
14h
13h
12h
11h
10h
0Fh
09h
08h
07h
06h
05h
04h
03h
02h
01h
00h
/OSCEN
reserved
WDE
WTR
SNL
D7
0
0
0
0
0
0
reserved
POR
D6
CF
0
0
0
0
-
-
10 years
Battery-backed =
10 seconds
10 minutes
reserved
CALS
D5
FC
LB
0
0
-
Serial Number Byte 7
Serial Number Byte 6
Serial Number Byte 5
Serial Number Byte 4
Serial Number Byte 3
Serial Number Byte 2
Serial Number Byte 1
Serial Number Byte 0
10 hours
10 date
Counter 2 MSB
Counter 1 MSB
Counter 2 LSB
Counter 1 LSB
reserved
WDT4
10 mo
CAL4
WP1
D4
0
-
Default Register Values
Address
reserved
18h
17h
16h
15h
14h
13h
12h
11h
0Bh
0Ah
01h
WDT3
CAL3
WR3
WP0
RC
D3
0
Hex Value
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x1F
0x80
WDT2
CAL2
WR2
VBC
CAL
CC
D2
FM31L278/L276/L274/L272 - 3V I2C Companion
seconds
minutes
months
years
hours
date
WDT1
CAL1
WR1
C2P
day
D1
W
-
WDT0
CAL0
WR0
C1P
VTP
D0
R
Function
Serial Number 7
Serial Number 6
Serial Number 5
Serial Number 4
Serial Number 3
Serial Number 2
Serial Number 1
Serial Number 0
Event Counter 2 MSB
Event Counter 2 LSB
Event Counter 1 MSB
Event Counter 1 LSB
Event Count Control
Companion Control
Watchdog Control
Watchdog Restart/Flags
Years
Month
Date
Day
Hours
Minutes
Seconds
CAL/Control
RTC Control
Page 11 of 26
Range
FFh
FFh
FFh
FFh
FFh
FFh
FFh
FFh
FFh
FFh
FFh
FFh
00-99
1-12
1-31
1-7
0-23
0-59
0-59