DS2703K Maxim Integrated, DS2703K Datasheet - Page 9

• Manufacturer Part Number: DS2703K
• Description: Battery Management
• Manufacturer: Maxim Integrated
• Series: DS2703r

the Search ROM button as well as be displayed in the ROM ID text boxes in the SHA-1 Commands
Sections. This ROM ID will be used for the Match ROM portion of the communication. If no ROM ID
is selected, a Skip ROM command will be used.
OTHER COMMANDS
The Other Commands Section contains 4 other commands of the DS2703: Activate THM, Clear Over
Drive Mode, Set Over Drive Mode, and Soft POR.
Activate THM
The user can left-click on the Activate THM button to send the Activate THM command to the device,
which drives the THM pin low. This allows the user to measure the voltage of the thermistor divider at
the THM pad of the evaluation board. The software will drive the GPIO pin (Pin 2 of the RJ-11
connector) low in order to disable DQ by opening the analog switch (MAX4676) on the evaluation board,
as shown in Figure 1. Measurement of the thermistor divider must be performed within 100mS of the
command being sent to the device. Therefore, the software will send a low pulse onto the Trigger
(TGRG) pad of the evaluation board to notify the host system to make the thermistor measurement.
Figure 3 below shows the timing of this sequence.
Set/Clear Over Drive Mode
The user can left-click on the Clear Over Drive Mode or Set Over Drive Mode to send the command to
the device to configure the device to communicate in Regular 1-Wire Speed or in Over Drive Speed. It is
important that the software and the device are communicating at the same speed in order for these
commands to have any affect. After either of these buttons has been clicked, the software will send the
command at the current 1-Wire speed, and then will switch the software to the appropriate speed.
Note: The user must provide a 15 Volt Programming voltage to the evaluation board in order for the 1-
Wire speed to be altered.
TRIGGER
Activate THM
Command
GPIO
DQ
Figure 3: Sequence for measuring the thermistor voltage
Measurement Trigger Pulse
Disable DQ
Measure THM Voltage
100mS
9 of 11
Resume
Normal
Operation