M48T37Y-70MH1E STMicroelectronics, M48T37Y-70MH1E Datasheet - Page 14

• Manufacturer Part Number: M48T37Y-70MH1E
• Description: IC TIMEKPR NVRAM 256KBIT5V 44SOH
• Manufacturer: STMicroelectronics
• Series: Timekeeper®r
• Type: Clock/Calendar/NVSRAMr

Specifications of M48T37Y-70MH1E

• Memory Size: 256K (32K x 8)
• Time Format: HH:MM:SS (24 hr)
• Date Format: YY-MM-DD-dd
• Interface: Parallel
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 44-SOH
• Bus Type: Parallel
• User Ram: 32KB
• Operating Supply Voltage (typ): 5V
• Package Type: SOH
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• Operating Temperature Classification: Commercial
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Pin Count: 44
• Mounting: Surface Mount
• Memory Configuration: 32K X 8
• Nvram Features: RTC
• Interface Type: Parallel
• Access Time: 70ns
• Supply Voltage Range: 4.5V To 5.5V
• Memory Case Style: SOIC
• No. Of Pins: 44
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-2854-5; M48T37Y-70MH1

Clock operations
3.4
Note:
14/30
Setting the alarm clock
Registers 7FF5h-7FF2h contain the alarm settings. The alarm can be configured to go off at
a predetermined time on a specific day of the month or repeat every day, hour, minute, or
second. It can also be programmed to go off while the M48T37Y/V is in the battery backup
mode of operation to serve as a system wake-up call.
RPT1-RPT4 put the alarm in the repeat mode of operation.
configurations. Codes not listed in the table default to the once per second mode to quickly
alert the user of an incorrect alarm setting.
User must transition address (or toggle chip enable) to see flag bit change.
When the clock information matches the alarm clock settings based on the match criteria
defined by RPT1-RPT4, AF is set. If AFE is also set, the alarm condition activates the
IRQ/FT pin. To disable alarm, write '0' to the alarm date registers and RPT1-4. The alarm
flag and the IRQ/FT output are cleared by a READ to the flags register as shown in
A subsequent READ of the flags register is necessary to see that the value of the alarm flag
has been reset to '0.'
The IRQ/FT pin can also be activated in the battery backup mode. The IRQ/FT will go low if
an alarm occurs and both the alarm in battery backup mode enable (ABE) and the AFE are
set. The ABE and AFE bits are reset during power-up, therefore an alarm generated during
power-up will only set AF. The user can read the flag register at system boot-up to
determine if an alarm was generated while the M48T37Y/V was in the deselect mode during
power-up.
Figure 7.
Table 6.
RPT4
1
1
1
1
0
A0-A14
ACTIVE FLAG BIT
IRQ/FT
Figure 8
Alarm interrupt reset waveform
Alarm repeat modes
illustrates the backup mode alarm timing.
RPT3
1
1
1
0
0
Doc ID 7019 Rev 9
RPT2
1
1
0
0
0
ADDRESS 7FF0h
15ns Min
RPT1
1
0
0
0
0
Table 6
shows the possible
Once per second
Alarm activated
Once per minute
Once per month
Once per hour
Once per day
M48T37Y, M48T37V
Figure
AI01677B
7.