Owner's manual

MAX6575L/H
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 microcon-
troller takes in temperature values from both sensors,
T1 and T2, on a single port pin, P3.7. The microcon-
troller 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.
SOT Temperature Sensor with
Multidrop Single-Wire Digital Interface
6 _______________________________________________________________________________________
GND
TS0
TS1
I/O I/O
0.1µF
V
DD
V
DD
MAX6575L MAX6575L
+2.7V TO +5.5V +2.7V TO +5.5V
GND
X2
X1
P3.7
P3.5
10k
OPEN: T1
CLOSED: T2
470Ω (8)
V
CC
V
CC
10k
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
Figure 2. Interfacing Multiple Devices with a Microcontroller