BQ27541-V200_1007 Datasheet, PDF (20/43 Pages) Texas Instruments – Single Cell Li-Ion Battery Fuel Gauge for Battery Pack Integration

bq27541-V200
SLUSA11 – FEBRUARY 2010
www.ti.com
SECURITY MODE
FULL ACCESS
UNSEALED
SEALED
Table 6. Data Flash Access
DATA FLASH
R/W
R/W
None
MANUFACTURER INFORMATION
R/W
R/W
R (A); R/W (B,C)
Although FULL ACCESS and UNSEALED modes appear identical, only FULL ACCESS mode allows the
bq27541 to write access-mode transition keys.
SEALING/UNSEALING DATA FLASH
The bq27541 implements a key-access scheme to transition between SELAED, UNSEALED, and
FULL-ACCESS modes. Each transition requires that a unique set of two keys be sent to the bq27541 via the
Control( ) control command. The keys must be sent consecutively, with no other data being written to the
Control( ) register in between. Note that to avoid conflict, the keys must be different from the codes presented in
the CNTL DATA column of Table 2 subcommands.
When in SEALED mode the [SS] bit of CONTROL_STATUS is set, but when the UNSEAL keys are correctly
received by the bq27541, the [SS] bit is cleared. When the full-access keys are correctly received then the
CONTROL_STATUS [FAS] bit is cleared.
Both Unseal Key and Full-Access Key have two words and are stored in data flash. The first word is Key 0 and
the second word is Key 1. The order of the keys sent to bq27541 are Key 1 followed by Key 0. The order of the
bytes for each key entered through the Control( ) command is the reverse of what is read from the part. For an
example, if the Unseal Key is 0x56781234, key 1 is 0x1234 and key 0 is 0x5678. Then Control( ) should supply
0x3412 and 0x7856 to unseal the part. The Unseal key and the FULL-ACCESS key can only be updated when
in FULL-ACCESS mode. .
DATA FLASH SUMMARY
Table 7 summarizes the data flash locations available to the user, including their default, minimum, and
maximum values.
Class
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
Subclass
ID
2
2
2
2
2
2
32
32
32
34
34
34
34
36
36
36
36
36
36
36
36
Subclass
Safety
Safety
Safety
Safety
Safety
Safety
Charge Inhibit Cfg
Charge Inhibit Cfg
Charge Inhibit Cfg
Charge
Charge
Charge
Charge
Charge Termination
Charge Termination
Charge Termination
Charge Termination
Charge Termination
Charge Termination
Charge Termination
Charge Termination
Table 7. Data Flash Summary
Offset
0
2
3
5
7
8
0
2
4
2
4
6
8
2
4
6
8
9
10
11
12
Name
OT Chg
OT Chg Time
OT Chg Recovery
OT Dsg
OT Dsg Time
OT Dsg Recovery
Chg Inhibit Temp Low
Chg Inhibit Temp High
Temp Hys
Charging Voltage
Delta Temp
Suspend Low Temp
Suspend High Temp
Taper Current
Min Taper Capacity
Taper Voltage
Current Taper Window
TCA Set %
TCA Clear %
FC Set %
FC Clear %
Data
Type
I2
U1
I2
I2
U1
I2
I2
I2
I2
I2
I2
I2
I2
I2
I2
I2
U1
I1
I1
I1
I1
Min Value Max Value Default Value
0
0
0
0
0
0
–400
–400
0
0
0
–400
–400
0
0
0
0
–1
–1
–1
–1
1200
60
1200
1200
60
1200
1200
1200
100
4600
500
1200
1200
1000
1000
1000
60
100
100
100
100
550
2
500
600
2
550
0
450
50
4200
50
-50
50
100
25
100
40
99
95
100
98
Units
0.1°C
s
0.1°C
0.1°C
s
0.1°C
0.1°C
0.1°C
0.1°C
mV
0.1°C
0.1°C
0.1°C
mA
0.01 mAh
mV
s
%
%
%
%
20
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