Glenayre Electronics Inc. GL-T8600-CN Manual Do Utilizador
DSP Exciter
Glenayre Document Number: 9110.00172
THEORY OF OPERATION
Issue 1, Rev. I: 01/15/97
Page: 6-8
Copyright © 1997 Glenayre
Print Date: 02/19/97
Synthesizer-1 also performs all communications between the IF stage circuit and the MCU
control circuit. A control input specifies the VCO-1 carrier frequency; this data is received
over a serial data link when the exciter is booting or changing channels. Status outputs are
a lock fault and a VCO1 level. The lock fault indicates loss of the carrier/reference phase
lock. The VCO1 level is the VCO-1 control voltage.
control circuit. A control input specifies the VCO-1 carrier frequency; this data is received
over a serial data link when the exciter is booting or changing channels. Status outputs are
a lock fault and a VCO1 level. The lock fault indicates loss of the carrier/reference phase
lock. The VCO1 level is the VCO-1 control voltage.
6.5
MCU
. Control outputs are
supplied by the MCU control circuit to the other functional circuits. Likewise, status inputs
are applied to the MCU control circuit from the other functional circuits. Discussions of
these control and status signals are included with the information on the other major func-
tional circuits. To interface these control and status signals, the MCU control circuit
contains an MCU, D/A converter, 8/16 bit converter, read-only memory, and a VSWR-fault
detector. To light the front-panel LEDs, the MCU control circuit contains a bank of PNP
switching transistors.
are applied to the MCU control circuit from the other functional circuits. Discussions of
these control and status signals are included with the information on the other major func-
tional circuits. To interface these control and status signals, the MCU control circuit
contains an MCU, D/A converter, 8/16 bit converter, read-only memory, and a VSWR-fault
detector. To light the front-panel LEDs, the MCU control circuit contains a bank of PNP
switching transistors.
, in the following
text which describes this circuitry and its signal flow.
6.5.1
Microcontroller Unit (MCU)
The MCU contains a central processing unit (CPU), memories, peripherals, and other
hardware on a single chip. The primary internal functions of the MCU and their application
in the exciter are described in the following list.
hardware on a single chip. The primary internal functions of the MCU and their application
in the exciter are described in the following list.
•
An eight-bit remote input port accepts discrete low power mode, emission mode, keyline,
and channel selects from the controller interface circuit. An external edge detector is
required to input the channel selects.
and channel selects from the controller interface circuit. An external edge detector is
required to input the channel selects.
•
Interrupt logic stops RF transmission when a fault or reset input is received, e.g. a VSWR
or PA fault.
or PA fault.
•
An on-board oscillator/clock generator, driven by an external crystal, times internal
MCU functions. A synchronized clock output times external functions.
MCU functions. A synchronized clock output times external functions.
•
The MCU performs most interfacing through a parallel communications link: eight-bit
data bus, sixteen-bit address bus, and a read/write line. External input and output latches
expand the capability of this link.
data bus, sixteen-bit address bus, and a read/write line. External input and output latches
expand the capability of this link.
•
An eight-bit input/output port supplies discrete keyline, RF status, and chip select
controls to the exciter and the PA.
controls to the exciter and the PA.
•
A serial peripheral interface (SPI) supplies synchronous serial frequency data to the IF
stage and RF stage circuits. Individual commands load the program into either IF stage’s
synthesizer-1 or RF stage synthesizer-2.
stage and RF stage circuits. Individual commands load the program into either IF stage’s
synthesizer-1 or RF stage synthesizer-2.
•
An 8-input analog-to-digital (A/D) converter measures voltage inputs from the exciter
and the PA. An external multiplexer expands MCU analog inputs to fifteen.
and the PA. An external multiplexer expands MCU analog inputs to fifteen.
•
A serial communications interface (SCI) exchanges asynchronous serial RS-232 data
with the VT-100 VDT. An external RS-232 driver buffers the MCU data, allowing it to
be exchanged through external connector J3.
with the VT-100 VDT. An external RS-232 driver buffers the MCU data, allowing it to
be exchanged through external connector J3.
•
A random-access memory (RAM) temporarily stores transmitter fault and alarm values.