Intermec 074787-001 User Manual
Chapter 2 — Theory of Operation
20
PB42 Portable Receipt Printer Service Manual
Error Detection
When the print controller encounters an error condition it asserts the
ERROR* interrupt (IRQ7). The error type is encoded on three signals:
ERR0, ERR1, and ERR2. These are connected, respectively, to bits 2, 1,
and 0 of the input shift register. The error codes are given in the table
below:
ERROR* interrupt (IRQ7). The error type is encoded on three signals:
ERR0, ERR1, and ERR2. These are connected, respectively, to bits 2, 1,
and 0 of the input shift register. The error codes are given in the table
below:
Upon receipt of an ERROR* interrupt the error code should be read by the
processor through the input shift register. See section 2.6.2 Input/Output
Shift Registers for details.
processor through the input shift register. See section 2.6.2 Input/Output
Shift Registers for details.
Thermistors and Paper Sensors
The print controller monitors the temperature of both the print head and
the ambient air (main PCB). These thermistors are also connected to the
serial ADC. The print head thermistor, SHTH is connected to channel 4
and the ambient thermistor, ENVT, is connected to channel 0.
the ambient air (main PCB). These thermistors are also connected to the
serial ADC. The print head thermistor, SHTH is connected to channel 4
and the ambient thermistor, ENVT, is connected to channel 0.
There are 3 optical paper sensor outputs that can be read by the processor:
• PAPER_SENSOR0
• PAPER_SENSOR1
• PAPER_SENSOR2
The first two are also monitored by the print controller. They are
respectively connected to ADC channels 1, 2, and 3.
respectively connected to ADC channels 1, 2, and 3.
The last two (1 and 2) are optional sensors that are connected to Auxiliary
Sensor Connector, J3. These can be used as mark and/or gap sensors. These
sensors are not used in the PB42.
Sensor Connector, J3. These can be used as mark and/or gap sensors. These
sensors are not used in the PB42.
PAPER_SENSOR0 is an out-of-paper sensor. Since this is also monitored
by the print controller, an out of paper condition will generate a print
controller error.
by the print controller, an out of paper condition will generate a print
controller error.
For details on how to read voltages of the thermistors and paper sensors, see
Error Codes
Printer Status
!ERROR
ERR0
ERR1
ERR2
Initialize
Low
Low
Low
Low
Hardware error
Low
High
Low
Low
Out-of-paper error
Low
High
High
High
Platen position error
Lor
Low
High
High
V
p
voltage error
Low
High
Low
High
Head temperature error
Low
Low
Low
High
Stop mode
High
High
High
High
Return-waiting status
High
High
Low
High
Print-ready status
High
Low
Low
High