Temperature Sensor and
System Monitor in a 10-Pin µMAX
MAX6683
Table 4. Configuration Register (Address 40h, Power-On Default = 08h)
BIT
NAME
READ/WRITE
DESCRIPTION
This bit controls the monitoring loop. Setting the bit to zero stops the
monitoring loop and puts the device into shutdown mode. The I
2
C/SMBus
interface is still active during the shutdown mode. Setting the bit to 1 starts the
monitoring cycle. All high/low limits should be set before setting this bit to 1.
This bit is used to enable or disable the
ALERT
output. Setting the bit to 1
enables the
ALERT
output; setting the bit to 0 disables the
ALERT
output.
—
This bit is used to clear the
ALERT
output when it is set to high. It does not
affect the Interrupt Status Register. The monitoring loop does not start until the
bit is set to zero.
This bit controls the internal clock frequency. Setting the bit to 1 changes the
clock frequency to 51.2kHz from 61.4kHz. This can improve the measurement
accuracy when the power-line frequency is at 50Hz.
This bit reduces the conversion time by a factor of 4 when it is set to 1.
—
This bit is used as a reset signal for the register initialization. The 1 of this bit
resets all the register values into the power-up default mode, including bit 7
itself.
0
Start/Stop
R/W
1
2
3
ALERT
Enable
Reserved
ALERT
Clear
R/W
—
R/W
4
5
6
7
Line Frequency
Select
Short Cycle
Reserved
Reset
R/W
R/W
—
R/W
Table 5. Interrupt Status Register (Address 41h, Power-Up Default = 00h)
BIT
0
1
2
3
NAME
2.5V
IN
-Error
1.8V
IN
-Error
5V
IN
-Error
V
CC
-Error
READ/WRITE
R
R
R
R
DESCRIPTION
A 1 indicates either a high or low limit has been exceeded at the 2.5V
IN
input.
A 1 indicates either a high or low limit has been exceeded at the 1.8V
IN
input.
A 1 indicates either a high or low limit has been exceeded at the 5V
IN
input.
A 1 indicates either a high or low limit has been exceeded at the V
CC
input.
A 1 indicates either a high or low limit has been exceeded at the internal
temperature sensor. The conditions that generate and clear this bit depend
on the temperature interrupt mode selected by bits 0 and 1 in the
Temperature Configuration Register.
—
4
Temp-Error
R
5, 6, 7
Reserved
—
The POR state of the T
HOT
register is 0101 0000 or
+80°C. The POR state of the T
HYST
register is 0100
0001 or +65°C.
High and low limits for the voltage inputs are stored in
registers 2Bh through 32h. If a measured voltage is less
than V
LOW
or greater than V
HIGH
, an
ALERT
is asserted.
The POR states of the high and low voltage limits are
1.1 and 0.9 times the nominal voltage for each input.
Interrupt Status Byte Functions
The Interrupt Status Register records temperature or
voltage fault conditions whenever a limit is exceeded
(Table 5). Bits 0 through 3 correspond to the 2.5V, 1.8V,
5V, and V
CC
voltage inputs and bit 4 corresponds to
the temperature. If a threshold has been crossed, the
appropriate bit contains a 1. In the default and one-time
interrupt modes, reading the status register clears the
register until a new out-of-range condition is detected.
8
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