Rainbow Electronics DS1846 User Manual
Page 2
DS1846
2 of 16
o
The EEPROM memory allows a user to store configuration or calibration data for a specific system or
device as well as provide control of the potentiometer wiper settings. Any type of user information may
reside in the first 248 bytes of this memory. The next three bytes of memory are for potentiometer
settings and the top five addresses of EEPROM memory are reserved. These reserved and potentiometer
registers should not be used for data storage. Access to this EEPROM is via an industry standard 2-wire
bus. The interface I/O pins consist of SDA and SCL. The wiper positions of the DS1846, as well as
EEPROM data, can be hardware write-protected using the Write Protect (WP) input pin.
The MicroMonitor is a precision temperature-compensated reference and comparator that monitors
certain vital status conditions for a microprocessor. When a sense input detects an out-of-tolerance Vcc
condition, a non-maskable interrupt is generated. As the voltage at the device degrades, an internal power
fail signal is generated that can be used to reset the processor. When Vcc returns to an in-tolerance level,
the reset signal is kept in the active state for a minimum of 130 ms to allow for the stabilization of the
power supply and the microprocessor. The MicroMonitor also functions as a pushbutton reset control.
The pushbutton input is debounced internally and is generated with an active pulse width of 130 ms
minimum.
Additionally, the DS1846 will operate from 3 volt or 5 volt supplies. One package option is available:
20-pin TSSOP.
DS1846 BLOCK DIAGRAM Figure 1
VCC
GND
SDA
SCL
WP
A0
PBRST
NMI
IN
RST
RST
248 BYTES
EEPROM
MEMORY
5 RESERVED
BYTES
1 BYTE WIPER
SETTING
POT 0
1 BYTE WIPER
SETTING
POT 1
1 BYTE WIPER
SETTING
POT 2
MICRO-
MONITOR
CONTROL
DATA
2-WIRE
INTERFACE
POTENTIOMETER 1
POTENTIOMETER 0
POTENTIOMETER 2
H0
W0
L0
H1
W1
L1
H2
W2
L2