34 Network Circuitry TB9100 Reciter Service Manual
© Tait Electronics Limited January 2006
is converted to analog signals by a CODEC chip. However, the CODEC
chip configuration is controlled by the RISC processor rather than the DSP.
The DSP block (see “DSP” on page 65) contains the DSP chip, which acts
as a peripheral processor to the RISC processor. The RISC processor can
communicate with the DSP through a host port interface, whereby the
RISC processor can access the DSP’s memory as though it existed in the
RISC processor’s memory space. The DSP block does not contain any
memory external to the DSP chip itself.
Two high-speed serial ports provide I/O capabilities for the DSP; one
connects to the CODEC in the audio interface, the other connects, via
J102, to the DSP on the reciter board. The RISC processor can also connect
to the reciter DSP through this same high speed serial port, but this interface
is not presently used in the ASIF application.
The clock oscillator block contains a clock oscillator for the RISC processor
and a clock buffer to buffer the clock from the reciter board before being fed
to the DSP. The power supply block contains several power convertors that
convert the incoming +28V supply to the various power supply voltages
required by the ASIF circuitry. The power supply block also includes the
power-on reset circuitry
5.1.1 Connectors
On the rear panel of the ASIF there are three connectors for external I/O:
■ DB9 connector, J103, connects to external digital I/O and a basic
RS-232 serial port
■ RJ45 connector, J104, connects the ethernet port
■ RJ45 connector, J105, connects the 4W audio and E&M signalling port.
Although both J104 and J105 use the same type of connector, J105 is keyed
to prevent its plug being accidentally inserted into J104. This prevents the
potentially high voltages on the E&M lines from damaging the ethernet
interface.
Along the top edge of the ASIF PCB there are two connectors for
interfacing to the reciter:
■ FFC connector J101 connects power and miscellaneous digital signals
from the reciter along with serial ports from the reciter RISC
■ PCB connector J102 connects signals through from the reciter DSP
Two further internal connectors are used for debug and program loading
purposes:
■ Micro-match connector J100 is used as the debug and program loading
port for the RISC processor
■ Micro-match connector J106 provides a JTAG interface to the DSP for
software debug purposes
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