Rainbow Electronics MAX6681 - Manual (Page 14)

MAX6680/MAX6681
autonomous mode (RUN/STOP = 0). This variable rate
control can be used to reduce the supply current in
portable-equipment applications. The conversion rate
byte’s POR state is 02h (0.25Hz). The MAX6680/
MAX6681 use only the 3LSBs of this register. The
5MSBs are “don’t care” and should be set to zero when
possible. The conversion rate tolerance is ±25% at any
rate setting. Valid A/D conversion results for both channels are avail-
able one total conversion time (125ms nominal, 156ms
maximum) after initiating a conversion, whether conver-
sion is initiated through the RUN/STOP bit, hardware
STBY pin, One-Shot command, or initial power-up.
Slave Addresses
The MAX6680/MAX6681 device address can be initially
set to nine different values by pin strapping ADD0 and
ADD1 so that more than one MAX6680/MAX6681 can
±1°C Fail-Safe Remote/Local Temperature
Sensors with SMBus Interface
14 ______________________________________________________________________________________
BIT NAME POR STATE FUNCTION
7 (MSB) ALERT MASK 0
Mask ALERT active state when 1. When 1, ALERT does not respond to
any fault related to the four limit registers.
6 RUN/STOP 0
Standby mode control bit; if 1, immediately stops converting and enters
standby mode. If zero, it converts in either one-shot or timer mode.
5 SPNP 1
When 1, the remote sensor is a common-collector substrate PNP. When
zero, the remote sensor is a diode-connected transistor.
4 Extended Resolution 0
When zero, remote- and local-sensors’ temperature data are 7 bits +
sign with 1°C resolution. When 1, the remote-sensor temperature data is
10 bits + sign with 0.125°C resolution.
3 Extended Range 0 Extended temperature range. 0 = normal, 1 = extended to -64°C.
2 SMBus Timeout 0
When set to 1, it disables the SMBus timeout, as well as the alert
response.
1 Software Reset 0 Software reset from SMBus from customer.
0 RFU 0 Reserved
Table 6. Configuration-Byte Bit Assignment
BIT NAME
POR
STATE
FUNCTION
7 (MSB) BUSY 0 When 1, the A/D is busy converting.
6 LHIGH 0
When 1, internal high-temperature alarm has tripped; cleared by POR or readout
of the Status register, if the fault condition no longer exists.
5 LLOW 0
When 1, internal low-temperature alarm has tripped; cleared by POR or readout of
the Status register, if the fault condition no longer exists.
4 RHIGH 0
When 1, external high-temperature alarm has tripped; cleared by POR or readout
of the Status register, if the fault condition no longer exists.
3 RLOW 0
When 1, external low-temperature alarm has tripped; cleared by POR or readout of
the Status register if the fault condition no longer exists.
2 OPEN 0
When 1 indicates an external diode open; cleared by POR or readout of the Status
register, if the fault condition no longer exists.
1 OVI 0 When 1, internal temperature exceeds the RWOI limit.
0 OVE 0 When 1, external temperature exceeds the RWOE limit.
Table 7. Status Register Bit Assignments