Specifications

E–7Principles of Operation
the ribbon/shuttle processor (RSP) is a 2400 baud asynchronous serial line. A
message protocol is used to communicate ribbon and shuttle information.
Fault Monitoring
The RTPU also monitors the hammer driver, mechanism driver, and the
electro–mechanical sensors for fault conditions. Fault conditions are reported
to the DPU.
Hammer Bank and Hammer Driver Faults
The FTIC works with the hammer driver ASIC to monitor coil shorts, opens,
average upper driven phase current, and temperature conditions. The RTPU
reads the FTIC registers to determine out–of–range conditions, and these are
passed on to the DPU.
Paper Faults
Two kinds of paper faults can occur: paper out and paper jammed. Both of
these conditions are monitored through optical sensors. The paper feed
controller watches the paper out and paper motion sensors and reports errors
to the RTPU. The RTPU passes this information on to the DPU.
Ribbon and Shuttle Faults
The mechanism driver ribbon and shuttle controller monitors fault conditions
in the drive circuits and notifies the RTPU if it finds errors. The RTPU can
also use the FTIC to measure time between magnetic pick–up (MPU) pulses,
enabling it to monitor shuttle speed and thus detect some shuttle faults.
CCB Hardware Overview
A Motorola 68010 microprocessor performs the DPU functions, a 64180
microprocessor handles the RTPU functions, and an 8032 micro–controller
serves as the paper feed controller (PFC), which is part of the RTPU. Actual
implementation of this hardware blurs the distinctions between the DPU and
RTPU, since the 68010 has access to the parallel port and the real–time
functions of the dot plucker, which are RTPU resources, while the 64180 has
access to the nonvolatile memory (NVRAM), which is a resource of the
DPU. These possibilities exist because of efficiencies in the hardware design;
software maintains the functional differences between the DPU and RTPU.
The CCB has four data buses. The 68010 has a local sixteen bit bus. The
64180 uses a local bus eight bits wide. A third bus is shared by the DPU and