Datasheet

S ADDR[6:0] 0 A CMD[7:0]
A Sr
ADDR[6:0]
1 A
DATA[7:0]
A
...
DATA[7:0]
N P
Address
0x7F
DataFrom
addr0x7F
DataFrom
addr0x00
S
ADDR[6:0]
0 A
CMD[7:0]
A
A
N
P
DATA[7:0]
DATA[7:0]
...
N
S ADDR[6:0] 0 A
CMD[7:0]
N P
S ADDR[6:0] 0 A CMD[7:0] A DATA[7:0] A P
S ADDR[6:0] 0 A CMD[7:0] A DATA[7:0] A P S ADDR[6:0] 1 A DATA[7:0] N P
S
ADDR[6:0]
0 A
CMD[7:0]
A Sr
ADDR[6:0] 1 A DATA[7:0]
N P
S ADDR[6:0] 0 A CMD[7:0]
A Sr
ADDR[6:0]
1 A
DATA[7:0]
A
...
DATA[7:0]
N P
(d)
(c)
(a) (b)
HostGenerated FuelGaugeGenerated
bq34z100
SLUSAU1B –MAY 2012–REVISED DECEMBER 2012 www.ti.com
The bq34z100 is shipped in the I
2
C mode. TI provides tools to enable the HDQ peripheral.
I
2
C INTERFACE
The gas gauge supports the standard I
2
C read, incremental read, one-byte write quick read, and functions. The
7-bit device address (ADDR) is the most significant 7 bits of the hex address and is fixed as 1010101. The 8-bit
device address is therefore 0xAA or 0xAB for write or read, respectively.
Figure 6. Supported I
2
C formats: (a) 1-byte write, (b) quick read, ©) 1 byte-read, and (d) incremental read
(S = Start, Sr = Repeated Start, A = Acknowledge, N = No Acknowledge, and P = Stop).
The “quick read” returns data at the address indicated by the address pointer. The address pointer, a register
internal to the I
2
C communication engine, increments whenever data is acknowledged by the bq34z100 or the
I
2
C master. “Quick writes” function in the same manner and are a convenient means of sending multiple bytes to
consecutive command locations (such as two-byte commands that require two bytes of data).
Attempt to write a read-only address (NACK after data sent by master):
Attempt to read an address above 0x7F (NACK command):
Attempt at incremental writes (NACK all extra data bytes sent):
Incremental read at the maximum allowed read address:
The I
2
C engine releases both SDA and SCL if the I
2
C bus is held low for t
BUSERR
. If the gas gauge was holding
the lines, releasing them frees the master to drive the lines. If an external condition is holding either of the lines
low, the I
2
C engine enters the low-power SLEEP mode.
DESIGN STEPS
For additional design guidelines, refer to the bq34z100EVM Wide Range Impedance Track Enabled Battery Fuel
Gauge User's Guide (SLUU904).
STEP 1: Review and Modify the Data Flash Configuration Data.
While many of the default parameters in the data flash will be suitable for most applications, the following should
first be reviewed and modified to match the intended application.
• Design Capacity: Enter the value in mAh for the battery, even if you plan to treat your application from the
“design energy” point of view.
• Design Energy: Enter the value in mWh.
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