3600 Printer Maintenance Manual
Channels 7 and 8 These outputs control the front panel LEDs. They can be set to high, low, or square wave outputs. The square wave output frequency is programmable.
Channel 9 This output is reserved. It has RXD as an input for autodetection of the serial communications parameters.
Channel 10 This is an input for the ribbon sensor. The channel detects transitions on the input. If it does not receive a transition before it receives a programmable number of links from channel 0, it interrupts the CPU to indicate a ribbon failure.
Channel 11 This output generates the refresh requests for the DRAM. It generates a low pulse at a programmable frequency and duration.
Channel 12 This is an input for the front panel switch. It detects transitions on the input, debounces the switch, and interrupts the CPU.
Channel 13 This output generates a square wave of a programmable frequency. It is used to set the current level for the motor driver circuit.
Channel 14 and 15 These channels are reserved to support a cutter or a wand port.
QSM
The QSM consists of two modules, a serial peripheral interface (SPI) and serial communications interface (SCI). The SPI is used to communicate with the A/D converter. It takes continuous readings and stores the values in RAM for immediate access by the CPU. The SCI is used for
Interrupt Priority Levels
The SIM module has seven IRQ pins to help facilitate external interrupts in the 3600:
∙/I/ORCV, /I/OXMT, /PFAIL, and HF are available as interrupts.
∙/I/ORCV and /I/OXMT are used for communications with the I/O option interface.
∙HF is used to indicate that the FIFO needs service.
∙/PFAIL indicates a loss of power.
∙The IRQ pins are used for general purpose I/O.
Crystal
The clock synthesizer of the MC68332 can operate from an
