Specifications

Smart Battery Charger Specification
SBS Implementers Forum -Page 7- Revision 1.1
4.4. Error Detection and Signaling
The Smart Battery Charger supports the SMBus method for error signaling. This error system is designed
to minimize the amount of traffic on the SMBus and the amount of code required to communicate with the
charger.
4.4.1. Error Detection
When a Smart Battery Charger detects an error condition (such as an unsupported command, data
unavailable, busy or bad data) it signals the master (Smart Battery or System Host) that an error has been
detected. All functions processed by the Smart Battery Charger are assumed to be error-free unless the
Smart Battery Charger signals the master device that an error has occurred.
4.4.2. Error Signaling
A Smart Battery Charger signals the SMBus master device that it has detected an unrecoverable error by
taking advantage of the SMBus requirement that an acknowledge bit must be sent by the slave after every
byte is transferred. When the Smart Battery Charger fails to provide the acknowledge bit, the SMBus
master device is obliged to generate a STOP condition, thus causing a premature termination of the
transfer. This signals the SMBus master device that an error has occurred.
The Smart Battery Charger must ALWAYS acknowledge its own address. Failure to do so may cause the
System Host or Smart Battery to incorrectly assume the Smart Battery Charger is NOT present in the
system. The Smart Battery Charger may choose not to acknowledge any byte following its address if it is
busy or otherwise unable to respond.