Key facts
- Brand
- STMicroelectronics
- Model
- M48T59
- Category
- Other Electronics
- Documents
- 2
- Languages
- EN
- Last added
- 2012-08-06
Start here
STMicroelectronics AN1216 Implementing a Periodic Alarm with TIMEKEEPER Application Note
The document describes the implementation of periodic alarm functionality for the TIMEKEEPER M48T59 and M48T59Y real-time clock (RTC) devices. It details how to configure the hardware registers to set alarms that repeat at specific intervals, such as every second, minute, hour, or day.
The guide provides software configuration steps in C language for an embedded microcontroller unit (MCU). It covers setting the alarm parameters, managing interrupt flags to prevent system jams, and handling data conversion between Binary-Coded Decimal (BCD) format used by the device and integer formats used by the software.
STMicroelectronics M48T59 specifications
| Supply Voltage | 5.0 V or 3.3 V |
|---|---|
| Memory Size | 64 Kbit (8 Kbit × 8) |
| Write‑Protect Voltage (M48T59) | 4.5 V < Vprp < 4.75 V |
| Write‑Protect Voltage (M48T59Y) | 4.2 V < Vprp < 4.5 V |
| Write‑Protect Voltage (M48T59V*) | 2.7 V < Vprp < 3.0 V |
| Package Types | 28‑pin PCDIP (CAPHAT) and 28‑lead SOIC (SNAPHAT) |
| Battery Backup | Lithium button cell integrated in CAPHAT/SNAPHAT package |
| Operating Temperature Range | 0 °C to 70 °C |
All STMicroelectronics M48T59 documents by type
How to use the product for one specific task, with worked examples.
Ratings, dimensions and ordering codes, for selection and design work.
Questions answered in these manuals
What devices does this application note support?
The document is specifically tailored for the M48T59 (or M48T59Y) device, though ideas can be adapted to other TIMEKEEPER devices with the alarm feature.
From: STMicroelectronics AN1216 Implementing a Periodic Alarm with TIMEKEEPER Application Note
How is the periodic alarm period defined?
The period is defined by setting specific Repeat bits (RPT4-RPT1) in the alarm registers and loading corresponding values into software variables for seconds, minutes, or hours.
From: STMicroelectronics AN1216 Implementing a Periodic Alarm with TIMEKEEPER Application Note
What supply voltage does the M48T59 operate at?
The device operates from either a 5.0 V or a 3.3 V supply.
How is the battery backup implemented in the M48T59?
A lithium button‑cell battery and crystal are integrated in the CAPHAT™ DIP or SNAPHAT™ SOIC package, providing backup power for the SRAM and RTC.