PS401-I/SS Microchip Technology, PS401-I/SS Datasheet - Page 17

• Manufacturer Part Number: PS401-I/SS
• Description: IC FUEL GAUGE BATTERY MGR 28SSOP
• Manufacturer: Microchip Technology

Specifications of PS401-I/SS

• Lead Free Status / RoHS Status: Request inventory verification / Request inventory verification

7.0
The PS401 uses a two-pin System Management Bus
(SMBus) protocol to communicate to the Host. One pin
is the clock and one is the data. The SMBus port
responds to all commands in the Smart Battery Data
Specification (SBData). To receive information about
the battery, the Host sends the appropriate commands
to the SMBus port. Certain alarms, warnings and
charging information may be sent to the Host by
the PS401 automatically. The SMBus protocol is
explained in this chapter. The SBData command set is
summarized in Table 7-1.
The PS401 SMBus communications port is fully
compliant with the System Management Bus Specifica-
tion, Version 1.1 and supports all previous and new
requirements, including bus time-outs (both slave and
master), multi-master arbitration, collision detection/
recovery and PEC (CRC-8) error checking. The SMBus
port serves as a Slave for both read and write functions,
as well as a Master for write word functions. SMBus
slave protocols supported include Read Word, Write
Word, Read Block and Write Block, all with or without
PEC (CRC-8) error correction. Master mode supports
Write Word protocols. The PS401 meets and exceeds
the Smart Battery Data Specification, Version 1.1/1.1a
requirements. The PS401 is compliant with System
Management Bus Specification 1.0.
The PS401 fully implements the Smart Battery Data
(SBData) Specification v1.1. The SBData Specification
defines the interface and data reporting mechanism for
an SBS compliant Smart Battery. It defines a consistent
set of battery data to be used by a power management
system to improve battery life and system run-time,
while providing the user with accurate information. This
is accomplished by incorporating fixed, measured,
calculated and predicted values, along with charging
and alarm messages, with a simple communications
mechanism between a Host system, Smart Batteries
and a Smart Charger.
The PS401 provides full implementation of the SBData
set with complete execution of all the data functions,
including sub-functions and control bits and flags,
compliance to the accuracy and granularity associated
with particular data values, and proper SMBus
protocols and timing.
7.1
The following subsections document the detailed
operation of all of the individual SBData commands.
7.1.1
Reports internal software version when read, opens
EEPROM for programming when written with the
password.
 2003 Microchip Technology Inc.
SMBus/SBData INTERFACE
SBData Function Description
ManufacturerAccess (0x00)
7.1.2
Sets or reads the low capacity alarm value. Whenever
the remaining capacity falls below the low capacity
alarm
warning messages to the SMBus Host with the
REMAINING_CAPACITY_ALARM bit set. A low
capacity alarm value of ‘0’ disables this alarm.
7.1.3
Sets or reads the remaining time alarm value.
Whenever the AverageTimeToEmpty falls below the
remaining time value, the Smart Battery sends alarm
warning messages to the SMBus Host with the
REMAINING_TIME_ALARM bit set. A remaining time
value of ‘0’ disables this alarm.
7.1.4
This function selects the various Battery Operational
modes and reports the battery's capabilities, modes
and condition.
Bit 0: INTERNAL_CHARGE_CONTROLLER
Bit set indicates that the battery pack contains its own
internal charge controller. When the bit is set, this
optional function is supported and the CHARGE_
CONTROLLER_ENABLED bit will be activated.
Bit 1: PRIMARY_BATTERY_SUPPORT
Bit set indicates that the battery pack has the ability to
act as either the primary or secondary battery in a
system. When the bit is set, this optional function is
supported and the PRIMARY_BATTERY bit will be
activated.
Bit 2-6: Reserved
Bit 7: CONDITION_FLAG
Bit set indicates that the battery is requesting a
conditioning cycle. This typically will consist of a full
charge to full discharge back to full charge of the pack.
The battery will clear this flag after it detects that a
conditioning cycle has been completed.
Bit 8: CHARGE_CONTROLLER_ENABLED
Bit is set to enable the battery pack's internal charge
controller. When this bit is cleared, the internal charge
controller is disabled (default). This bit is active only
when the INTERNAL_CHARGE_CONTROLLER bit is
set.
Bit 9: PRIMARY_BATTERY
Bit is set to enable a battery to operate as the primary
battery in a system. When this bit is cleared, the battery
operates in a secondary role (default). This bit is active
only when the PRIMARY_BATTERY_SUPPORT bit is
set.
value,
RemainingCapacityAlarm (0x01)
RemainingTimeAlarm (0x02)
BatteryMode (0x03)
the
Smart
Battery
DS40238B-page 17
PS401
sends
alarm