3
dc2423af
DEMO MANUAL DC2423A
OPERATING PRINCIPLES
JP5 & JP6:
I
2
C Address Configuration. JP5 corresponds
to ADR0 and JP6 to ADR1. The address pins are 3-state
inputs; they can be LO (V
EE
), open, or HI (V
CC2
). The default
stuffing is LO-LO, which corresponds to a device write
address of 0010000 (20h). An address of ADR0 = LO and
ADR1 = HI puts the LTM9100 in Single-Wire Broadcast
Mode, and free-running serial data appears on SDA. See
data sheet for additional details.
JP7:
Line Monitor Jumper. This jumper consists of two
shunts which can be placed in the HIGH SIDE or LOW
SIDE state as indicated. The default jumper is configura-
tion is HIGH SIDE. Improper setting will result in invalid
data representation of the input voltage at the ADIN pin.
I
2
C INTERFACE – J5
A simple means of exercising the I
2
C port is provided at
J5, to be used in conjunction with a PC and DC590 or
DC2026. The DC590 or DC2026 act as an intermediary
between DC2423A and a PC, complete with isolation.
Simply plug in the 14-wide interface cable from J5 to the
DC590 or DC2026.
The QuickEval software is found here:
www.linear.com/
designtools/software
. There is a ‘personality’ EEPROM near
the J5 connector which is read by the DC590 or DC2026
to automatically bring up the correct software. From there,
all of the LTM9100 registers can be read from or written
to, allowing full control over all of the device’s features.
Alternatively the DC2026 may be used as a gateway for
Arduino programming, example code provided at
www.
linear.com/product/LTM9100
.
To connect an external I
2
C interface, disconnect the DC590
or DC2026 and either use pins 4 and 7 on J5 or the SCL
and SDA test points located near J5. Note that the I
2
C
lines are referenced to V
L
and GND.
SINGLE WIRE INTERFACE
It is possible to operate the LTM9100 autonomously yet still
retain the monitoring functions by placing it in Single-Wire
Broadcast Mode. To do this, set the I
2
C address jumpers
to ADR0 = LO and ADR1 = HI. A serial data stream is then
observable on the SDA pin of J5 or SDA test point near
J5. See the LTM9100 data sheet for additional details.
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