FM33256B
Document Number: 001-86213 Rev. *C
Page 16 of 39
F(1:0)
Square Wave Frequency Select: These bits select the frequency on the ACS pin when the CAL and AL/SW bits are
both ‘0’. Nonvolatile.
Setting
F(1:0)
1 Hz
00 (default)
512 Hz
01
4096 Hz
10
32768 Hz
11
VBC
VBAK Charger Control: Setting VBC to ‘1’ (and FC = ‘0’) causes a 80 µA (1 mA if FC = ‘1’) trickle charge current to
be supplied on V
BAK
. Clearing VBC to ‘0’ disables the charge current. Battery-backed, read/write.
VBC
FC
Trickle charge current
0
X
Disabled
1
0
80 µA
1
1
1 mA
FC
Fast Charge: Setting FC to ‘1’ (and VBC = ‘1’) causes a ~1 mA trickle charge current to be supplied on V
BAK
.
Clearing VBC to ‘0’ disables the charge current. Battery-backed, read/write.
VTP(1:0)
VTP Select. These bits control the reset trip point for the low V
DD
reset function. Nonvolatile, read/write.
VTP
VTP1
VTP0
2.60 V
0
0 (factory default)
2.75 V
0
1
2.90 V
1
0
3.00 V
1
1
17h
Serial Number Byte 7
D7
D6
D5
D4
D3
D2
D1
D0
SN.63
SN.62
SN.61
SN.60
SN.59
SN.58
SN.57
SN.56
16h
Serial Number Byte 6
D7
D6
D5
D4
D3
D2
D1
D0
SN.55
SN.54
SN.53
SN.52
SN.51
SN.50
SN.49
SN.48
15h
Serial Number Byte 5
D7
D6
D5
D4
D3
D2
D1
D0
SN.47
SN.46
SN.45
SN.44
SN.43
SN.42
SN.41
SN.40
14h
Serial Number Byte 4
D7
D6
D5
D4
D3
D2
D1
D0
SN.39
SN.38
SN.37
SN.36
SN.35
SN.34
SN.33
SN.32
13h
Serial Number Byte 3
D7
D6
D5
D4
D3
D2
D1
D0
SN.31
SN.30
SN.29
SN.28
SN.27
SN.26
SN.25
SN.24
Table 7. Register Description
(continued)
Address
Description