MR-MINI-RTCTM I2C Real Time Clock Board
User Manual
Copyright © 2007 MicroResearch
GRAVITECH GROUP WWW.GRAVITECH.US
The MR-MINI-RTC is a Real Time Clock
(RTC) board. It display time base such as
clock, timer, and calendar. Moreover, it can
be a counter for an external clock. The data
can be interface via I2C bus. There are no
external components required. This makes it
perfect for embedded systems that need
RTC. The board is small can compact in size
2.20 x 1.70 inches.
There are two modes of operation RTC
mode and counter mode. When using RTC
mode, there is a variable capacitor for
frequency crystal adjustment. This makes
crystal create correct frequency result in
accurate time base. There is a on-board
battery backup when there is no power apply
to the board. This enable RTC to run
continuously even without power supply.
When using counter mode (CNT), user can
input pulse signal from external generated
source via a header pin. Moreover, there is
an on-board push button switch so user can
generate the pulse to test or experiment with
this feature.
The MR-MINI-RTC is designed base on
LM2575-5 IC. It is a clock/calendar circuit
based on a 2048-bit static CMOS RAM
organized as 256 words by 8 bits. Addresses
and data are transferred serially via the two-
line bidirectional I2C bus. The built-in word
address register is incremented
automatically after each written or read data
byte.
Please take a look at PCF8583 datasheet for
more information.
•I
2C bus interface operating supply
voltage: 2.5V to 6V
•Clock function with four year calendar
•24 or 12 hour format
•Thermal shutdown and current limit
protection
•On-board variable capacitor for
frequency adjustment
•Jumpers setting configuration
•Small and compact in size
•Four mounting holes on each corner
•Male and female output headers
There are two set of jumpers must be
configure. The first set is DIS/ENA jumpers.
These jumpers connect R pulled-up to SDA,
SCL and INT pins. If there are pulled-up
resistors on the bus already, these jumpers
need to be in disable (DIS) positions.
Otherwise, the jumpers need to be on
enable (ENA) position.
FIG 1: Pulled-up R enable FIG 2: Pulled-up R disable
Description Features:
Interfacing:
