DS2436 Dallas Semiconducotr, DS2436 Datasheet - Page 12

• Manufacturer Part Number: DS2436
• Description: Battery ID/Monitor Chip
• Manufacturer: Dallas Semiconducotr

STATUS REGISTER (62h-63h)
The Status Register is a 2-byte read only register at addresses 62h and 63h. Address 62h is the least
significant byte of the Status Register and is currently the only address with defined status bits; the other
byte at address 63h is reserved for future use. The Status Register is formatted as follows:
MSB
where
TB =
NVB =
LOCK =
ADB =
VOLTAGE REGISTER (77h-78h)
The onboard analog-to-digital converter (ADC) has 10 bits of resolution and will perform a conversion
when the DS2436 receives the command protocol (Convert V) [B4h]. The result of this measurement is
placed in the 2-byte Voltage Register (see Memory Map). The range for the DS2436 ADC is 0V to 10V;
this range is suitable for NiCd or NiMH battery packs up to six cells, and for lithium ion battery packs of
two cells. The full-scale range of the ADC is scaled to 10.24V, resulting in a resolution of 10 mV.
While the ADC has a range that extends to 0V, it is important to note that the battery voltage is also the
supply voltage to the DS2436. As such, the accuracy of the ADC begins to degrade below battery
voltages of 2.4volts, and the ability to make conversions is limited by the operating voltage range of the
DS2436.
Voltage is expressed in this register in straight binary format, as outlined in Table 2. Note that while
codes exits for values below 2.4volts, accuracy of the ADC and the limitation on the DS2436’s supply
voltage make it unlikely that these values would be used in actual practice.
0
1
Temperature Busy flag. 1 = temperature conversion in progress; 0 = temperature
conversion complete, valid data in temperature register.
Nonvolatile memory busy flag. 1 = Copy from scratchpad to EEPROM in progress, 0 =
nonvolatile memory is not busy. A copy to NV RAM may take from 2 ms to 10 ms (taking
longer at lower supply voltages).
1 indicates that NV1 is locked; 0 indicates that NV1 is unlocked. This status bit is
implemented in EEPROM in order to preserve its state even when the battery is
completely discharged.
A/D converter busy flag. 1 = analog-to-digital conversion in progress on battery voltage; 0
= conversion complete, no measurement being made. An A/D conversion takes
maximum of 10 ms.
0
1
0
1
0
1
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ADB
1
LOCK
1
NVB
1
TB
1
LSB
62h
63h
DS2436
a