Dynex DSX - Major Components of the EPOD; Removing the EPOD

The Electronics Pod Assembly (EPOD)
17-4 DSX™ System Service Manual
•
•
•
•
•
•
•
17.3.1 Major Components of the EPOD
MICROCOMPUTER - Overall operation of the module is based on the Hitachi H8/3337F
single-chip microcomputer. This microcomputer provides 60Kbytes of Flash ROM and
2Kbytes of RAM. The H8/3337F has the following internal peripheral capabilities:
9 ports, providing 58 I/O and 8 Input lines
Two 8-bit timers (TMR0, TMR1)
One 16-bit free-running counter (FRC)
Two digital to analog channels (DA0, DA1), with 8-bit resolution
Eight analog to digital channels (AN0 through AN7), with 10-bit resolution
Two serial communications channels (COM0, COM1)
Two pulse width modulation channels (PWM0, PWM1)
The H8/3337Y XTAL operating frequency is 16 MHz.
SERIAL COMMUNICATIONS WITH CONTROLLER – Commands and test data are
transferred between the H8 and the external PC controller via a serial RS-232 interface.
Interface drivers and receivers are used between the COM1 serial communications channel on
the H8 and the interface connector to provide proper RS-232 signal levels to the controller.
DTR is signalled via Port 6-7 and DSR is received on Port 6-5
VOLTAGE GENERATION AND REGULATION – DC voltage of +12 volts +/- 5% is
provided to the Comm Module from a power supply that is built into the EPOD. A linear
regulator converts the 12v to 5 volts to drive the logic devices.
17.3.2 Removing the EPOD
1 Remove the line power cord and the communications cable to the personal
computer from the EPOD.
2 Remove the drawer module.
3 Remove the racks from the right side of the workspace and then remove the plate
on the right rear side of the workspace.
4 Push the EPOD from the rear to release it from the back plane board.
Considerable force is required to release the connectors from the socket in the
back plane board.
5 Once the EPOD is freed from the back plane board, continue pushing it toward
the front of the unit and angle it up to remove it from the system. It may be
necessary to open the front extension to allow enough room for the EPOD to be
removed.