Datasheet

Interfacing Multiple Devices
with a Microcontroller
Figure 2 shows how to interface multiple MAX6575L/H
devices with an 8051 microcontroller. The first device, T1,
is configured for a timeout multiplier of 40μs/°K, while the
second device, T2, is configured for a timeout multiplier of
80μs/°K to avoid overlap. The microcontroller takes in tem-
perature values from both sensors, T1 and T2, on a single
port pin, P3.7. The microcontroller displays five times the
temperature in degrees Celsius in binary on Port 1. A
switch connected to a pull-up resistor at Port 3.5 selects
which temperature is displayed: open = T1, closed = T2.
Code is provided for this application as Listing 1.
Figure 2. Interfacing Multiple Devices with a Microcontroller
GND
TS0
TS1
I/OI/O
0.1µF
V
DD
V
DD
+2.7V TO +5.5V +2.7V TO +5.5V
GND
X2
X1
P3.7
P3.5
10kΩ
OPEN: T1
CLOSED: T2
470Ω (8)
V
CC
V
CC
10kΩ
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
8051
12MHz
22pF
22pF
GND
T2T1
TS0
80µs/°K40µs/°K
TS1
0.1µF
P1.0
MAX6575L MAX6575L
MAX6575L/H SOT Temperature Sensor with
Multidrop Single-Wire Digital Interface
www.maximintegrated.com
Maxim Integrated │ 6