Intermec 074787-001 User Manual

Charging initiation is automatic. When the print controller is disabled and 
external power is applied, either from the DC jack or the external charging 
contacts, the charging circuit is activated.

Each charging IC has two charging status outputs: CHARGING_[A,B]* 
and CHG_DONE_[A,B]*. These outputs behave according to the 
following table.

Generally, when the charger is charging CHARGING_[A,B]* is asserted, 
and when charging is complete CHG_DONE_[A,B]* is asserted. Software 
should be written to detect fault conditions based on the charger outputs.

CHARGING_A*, CHG_DONE_A*, CHARGING_B*, and 
CHG_DONE_A* can be read on the input shift register bits 7, 6, 5, and 4, 
respectively. See 

 for details on 

how to read the shift register.

Batteries A and B are connected to channels 5 and 6 of the ADC, 
respectively. See 

 for details on 

reading data from the ADC. 

The battery voltages are divided down so that a full battery corresponds to 
0xff. To convert the ADC output to the actual battery voltage, multiply by 
0.0343.

The battery voltages should be periodically monitored to detect the 
presence of a battery, and to report low battery capacity. Due to loading 
effects, the battery voltage can temporarily droop while printing. Because of 
this, software should use the average of several readings when comparing 
with the low battery threshold.

The LBO* interrupt generated from the 3.3 V DC-DC converter occurs 
when VBB, the diode “or” of the battery voltages, falls below 5.75 V. 

Precharge

Low

High

Fast charge

Low

High

Fault

1 Hz, 50% duty cycle

High

Charging done (>90%)

High

Low

Sleep mode

High

High

Thermistor invalid

High

High

Thermal shutdown

High

High

Battery absent

High

High