Serial Port 4 Transmit Clock Receiver Buffer Control (J20) - Motorola MVME2603-1121A Installation And Use Manual

MVME2603/2604 Base Board Preparation
1

Serial Port 4 Transmit Clock Receiver Buffer Control (J20)

1-12
As described in other sections, a complete configuration of Serial
Port 4 requires that you set the following jumper headers on the
MVME2603/2604 or the transition module:
J16 (Serial Port 4 receive clock configuration) on
MVME712M-compatible versions of the base board
J17 (Serial Port 4 transmit clock configuration)
J20 (Serial Port 4 transmit clock receiver buffer control) on
MVME712M-compatible versions of the base board
J15 on the MVME712M transition module or J3 on the
MVME761 (Serial Port 4 clock configuration)
A transmit clock receiver buffer (controlled by header J20) is
associated with Serial Port 4. Installing a jumper on J20 enables the
buffer. Removing the jumper disables the buffer. The factory
configuration has the Serial Port 4 buffer enabled.
J20 remains open on MVME761-compatible versions. On
MVME712M-compatible versions, J20 is set in tandem with J17 to
configure the Serial Port 4 transmit clock. If one deviates from the
factory configuration, so must the other. Figures 1-8/1-9 (for the
MVME712M) and Figures 1-14/1-15 (for the MVME761) diagram
the overall jumper settings required on the MVME2603/2604 and
transition module for a Serial Port 4 DCE or DTE configuration.
For additional details on the configuration of those headers, refer to
the MVME712M or MVME761 Transition Module sections or to the
userÕs manual for the transition module you are using (listed in the
Related Documentation appendix).
J20
2
1
Buffer Enabled
(factory configuration)
J20
2
1
Buffer Disabled