What's
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Section
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Please read this!
Errata to Smart Battery Data Set Specification
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An errata to the Smart
Battery Data Specification is being issued to correct recently
discovered inconsistencies between the 1.0 and 1.1 specification
SpecificationInfo() Revision and Version nibble definitions. As
presently defined, systems implementing the 1.1 specification
may not be able to correctly identify batteries built to the 1.0
specification. Download the full
errata here, Smart Battery Data Set Specification Errata, Version
1.1a.
Summary of the errata:
1. SpecificationInfo() has had the Revision and Version nibbles
combined into a SpecID byte. The values for 1.0, 1.1 without PEC
support and 1.1with PEC support are clearly listed:
* V1.0 SBData SpecInfo() = 0x0010
* V1.1 SBData, no PEC SpecInfo()=0x0021
* V1.1 SBData, with PEC SpecInfo()=0x0031
2. A minor change has been made to substitute
the word "re-learn" for "condition". There
has been some confusion about the meaning of "condition."
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5.1.4, 5.1.13,
5.1.21, 5.1.25, 5.4.1
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Smart Battery Charger
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The Smart Battery Charger
Specification, Revision 1.10, incorporates input from SBS developers
to clarify the original specification and adapt it to the current
industry practices in SBS system design.
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Global changes to the
document were made to update the thermistor pin to its
new name of safety signal, and to rename the Battery
Controlled and Host Controlled charger types to Level
2 and Level 3, respectively. All figures were updated
as necessary. Definitions for Programmatic Maximum and
PEC were added tot he Definitions section. The References
section was updated to refer to the latest SBS and other industry
specifications.
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All
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The definitions for
Level 2 and Level 3 charger types were re-written
and a table was added to illustrate their differences. A Level
2 charger is a slave device which is controlled by the Safety
Signal, ChargingCurrent(), ChargingVoltage() and AlarmWarning()
data from the battery. All other chargers are Level 3.
A Level 3 charger must poll for ChargingCurrent(), ChargingVoltage()
and AlarmWarning() data from the battery at least every minute.
It is suggested that this polling not occur more frequently than
every 5s. Level 2 chargers operate in a default mode that
assumes the Smart Battery?fs current and voltage scale factors
are unity. Only Level 3 chargers may use non-default scaling
factor values.
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4.2, 4.3, 5.2
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The accuracy definitions
for ChargingCurrent() and ChargingVoltage() have been changed
to meet the safety requirements of all battery chemistries. They
also promote charging to a higher capacity for chemistries which
use constant voltage charging. ChargingCurrent() must be "ñµ¥
of the programmatic maximum current or better." ChargingVoltage()
must be "+1%/-9% of the programmatic maximum voltage or better."
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5.1.1, 5.1.2,
5.2.1, 5.2.2
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No changes were made
to the ChargerMode() bits, however this function is defined to
be expressly write-only and can not be relied on to return meaningful
data if read.
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5.1.4
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In ChargerStatus(),
MASTER_MODE bit was renamed POLLING_ENABLED to communicate its
function more clearly, and the VOLTAGE_NOTREG and CURRENT_NOTREG
bits are specifically designated as optional as originally intended
in the V0.95 specification. Bits indicating the thermistor range
were renamed (THERM_OR to RES_OR, THERM_COLD to RES_COLD, THERM_HOT
to RES_HOT, THERM_UR to RES_UR). The descriptions of nearly all
bits were improved, without changing the original definitions.
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5.1.5
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ChargerSpecInfo() includes
two new values for the CHARGER_SPEC nibble. 0010 signifies support
for SBC 1.1 without PEC and 0011 signifies support for SBC 1.1
with PEC. A master device that wants to use the PEC protocols
will check CHARGER_SPEC to determine if the PEC protocols can
be used with the charger. All unused bits in ChargerSpecInfo()
must return a zero value when read.
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5.1.6
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The Safety Signal
ranges have been defined to include guard-banding to allow for
less than perfect detection of the ranges. The new ranges for
the safety signal in ohms are as follows: under-range (less
than 575), Hot (425 to 3150), Normal (2850 to 31.5k), Cold (28.5k
to 105k), over-range (95k or greater). The specification also
explicitly allows the use of discrete resistance values to control
charging and therefore, the 103AT thermistor curve in Appendix
F was deleted.
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6.1.1, Appx.
F
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Some miscellaneous
changes are: the wake-up charge description now allows an option
for host to set lower time-out than nominal period as added safety,
a recommended max leakage current of 100uA is specified to prevent
a charger from overcharging a pack when ChargingCurrent() = 0,
and the condition of RES_OR = 1 was added to state 15 of the transition
table in Sec 6.1.8. A note that SMB Alert and AlertResponse protocol
defined in the System Management Bus Specification are available
as interrupt mechanism was added to Sec 6.1.10.
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6.1.8, 6.1.10
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A section describing
non-DC charger output was added to Appendix D to caution the system
designer to consider the impact of charger output ripple on the
battery. The specification specifically allows pulse charging
if all system components are compatible with the particular pulse
method, and it is safe.
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Appx. D
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This Appendix has been
augmented to explain two methods of accurate charging, one by
using the battery's measurements and the other by using a charger
with a more precise output than intended in original SBS specifications.
Examples of required charger accuracy for lithium-ion pack configurations
are given.
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Appx. E
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Smart Battery Data
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Many items throughout
the specification were given more description and examples. Some
areas include error checking, data retries, and data update rates.
Where appropriate, tables were added to help in the clarification.
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All
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BatteryMode():
A new control bit was added to the BatteryMode() register. This
allows the disabling of the AlarmWarning() broadcasts for up to
60 seconds at a time. The bit must be re-written to continue to
suppress the alarm broadcasts.
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5.1.4
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CycleCount():
Instead of a defined value of 15% as in the V1.0 spec, the new
CycleCount() value is incremented when the accumulated discharge
capacity equals the value in DesignCapacity(). This then creates
an "odometer" value when CycleCount() is multiplied
by DesignCapacity(). The resulting value gives a estimate of the
total capacity a battery pack has delivered, regardless of the
depth of discharge or charge.
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5.1.22
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SMBus Protocols:
The SMBus revision 1.1 contains numerous updates. For one, an
error checking byte was added as an optional feature in the data
stream of some protocols. Since these protocols are detailed in
the SMBus Specification, the diagrams were removed from the SBData
Specification.
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6.1, 6.2, 6.3
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Smart Battery Selector
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The Smart Battery Selector
Specification, Revision 1.10, incorporates the changes of the
wording that was accepted in the rest of the SBS specification.
There was no impact to the implementation from this change.
The attempt to incorporate
the simultaneous charging and discharging are now incorporated
into the new Smart Battery Manager Specification 1.00, so this
selector specification does not handle simultaneous charging and
discharging functions.
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All
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Global change to the
document was made to update the thermistor pin to its new
name of safety signal. All figures were updated as necessary.
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All
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SelectorInfo()
includes two new values for the SELECTOR_REVISION nibble. 0010b
signifies support for Smart Battery Selector 1.1 without packet
error checking (PEC) and 0011b signifies support for Smart
Battery Selector 1.1 with PEC. A master device that wants to use
the PEC protocols will check SELECTOR_REVISION to determine if
the PEC protocols can be used with the selector.
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5.3
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Link to the System
Management Bus
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The System Management
Bus (SMBus) Specifications, Bus and BIOS, have been moved to the
SMBus Specs Page at: http://www.smbus.org/specs/
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