BQ2040SN-C408 BENCHMARQ, BQ2040SN-C408 Datasheet - Page 11

• Manufacturer Part Number: BQ2040SN-C408
• Description: BATTERY CHARGE MONITOR, SMD, 2040
• Manufacturer: BENCHMARQ

Specifications of BQ2040SN-C408

• Battery Management Function: Charger, Status Monitor
• Battery Type: Li-Ion / NiCd / NiMH
• Supply Voltage Range: 3V To 6.5V
• Battery Ic Case Style: SOIC
• No. Of Pins: 16
• Operating Temperature Range: 0°C
• Interface Type: 2-Wire, Serial

n
The particular protocol used is a function of the com-
mand. The protocols used are shown in Figure 3.
Host-to-bq2040 Messages (see Table 4)
ManufacturerAccess() (0x00)
This read/write word is an open location.
RemainingCapacityAlarm() (0x01)
This function sets or returns the low-capacity alarm
value. When RM falls below the RemainingCapac-
ityAlarm value initialized from the external EE-
PROM, the Remaining_Capacity_Alarm bit is set in
BatteryStatus. The system may alter this alarm dur-
ing operation.
RemainingTimeAlarm() (0x02)
This function sets or returns the low remaining time
alarm value. When the AverageTimeToEmpty falls be-
low this value, the Remaining_Time_Alarm bit in Bat-
teryStatus is set. The default value for this register is
programmed in EE 0x02-0x03.. The system may alter
this alarm during operation.
Read block
Input/Output: word.
Input/Output: unsigned integer. This sets/returns
the value where the Remaining_Capacity_Alarm
bit is set in Battery Status.
Units: mAh
Range: 0 to 65,535mAh
S
S
S
1
1
1
Byte Count =N
Battery Address
Battery Address
Battery Address
8
0001011
0001011
0001011
Data byte low
7
7
7
8
1
A
1
1
1
0
0
0
Data byte 1
Figure 3. Host Communication Protocols
1
A
A
A
A
1
1
1
8
Command Code
Command Code
Command Code
Data byte high
Read Word
Block Read
Write Word
8
8
8
8
A
1
Data byte 2
A
1
A
A
A
1
1
1
8
P
S
S
1
1
Data byte low
Battery Address
Battery Address
8
11
1
A
7
7
BatteryMode() (0x03)
This read/write word selects the various battery opera-
tional modes. The bq2040 supports the battery capacity
information specified in mAh. This function also deter-
mines whether the bq2040 charging values are broad-
casted to the Smart Battery Charger address.
Writing bit 14 to 1 disables voltage and current Master
Mode broadcasts to the Smart Battery Charger. Bit 14 is
automatically reset to 0 if SMBC and SMBD = 0 for
greater than 2 seconds (i.e. pack removal).
Writing bit 13 to 1 disables all Master Mode broadcasts
including alarm messages to the Smart Battery Charger
and Host. The bit remains set until overwritten. Pro-
gramming bit 3 of FLAGS2 in the EEPROM (EE0x3f)
initializes this bit to a 1.
Bit 7 is the condition request flag. It is set when the
bq2040 is initialized from the EEPROM and reset when a
learning cycle has been completed. It is also set to a 1 if
CycleCount increases by 32 without a new learning cycle.
AtRate() (0x04)
This read/write word is the first half of a two-function
set used to set the AtRate value used in calculations
made by the AtRateTimeToFull and AtRateTime-
ToEmpty.
Input/Output: unsigned integer. This sets/returns
the value where the Remaining_Time_Alarm bit is
set in Battery Status.
Units: minutes
Range: 0 to 65,535 minutes
Data byte N
A
1
Data byte high
1
1
1
1
8
1
1
A
A
8
A
1
A
1
P
1
P
1
A – ACKNOWLEDGE
A – NOT ACKNOWLEDGE
S – START
P – STOP
System Host
bq2040
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bq2040