User's Manual Part 3

Backplane/Interface Boards - 128 -
Affinity
®
LBD-200C-N1 Transmitter
Product Manual
Firmware Systems
The MSI contains four firmware programs: the Main MCU program, the Main CPLD program,
the Port MCU program, and the Port CPLD program. Interaction of the various firmware
programs is described below.
Main MCU Firmware
The Main MCU program (main firmware) is the most complex of the four programs. This
program is responsible for supporting the Local and Remote serial interfaces, MRO, and PAS
Manager, as well as passing commands to the Modulator, and receiving fault notifications from
the Modulator.
Remote Serial Bus Support
The main firmware receives TNET protocol Remote serial commands and requests. Commands
may be issued by using the Omnitronix SNMP Link SL81 management device. The commands
may be used to change the values of calibration variables stored in MSI non-volatile memory.
For a list of these variables, refer to the SNMP document.
Commands may also be issued to change the settings and behavior of the Modulator. Refer to
SNMP document for a list and description of the available Modulator commands. The main
firmware is stored in flash memory. The firmware may be updated using a terminal emulator to
issue updated commands to the transmitter, and to transfer the updated firmware file to the
transmitter.
Status of the Affinity® transmitter is collected by means of status queries sent to the MSI
Remote serial port. The MSI responds to these requests with a response message in a
predefined format, containing values of monitored variables. In transmitters having an internal
SNMP Device Server, the Device Server repeatedly polls the status of the Affinity® transmitter
with status queries sent to the MSI.
Local Serial Bus Support
The MSI Main MCU, through firmware, implements a master device on the Affinity® internal
Local serial bus. The master device issues requests and commands to the Upconverter on the
bus, which is a slave device (i.e. this node cannot issue a request or command, but can only
receive requests/commands and respond). Through frequent Local bus queries/responses, the
MSI collects the status of the Upconverter. In addition, the MSI can send commands to the plug-
in causing changes in operation such as: changing the operating channel, or setting the system
to STANDBY or ON AIR.
Master Reference Oscillator Support
The MSI main firmware monitors and controls the on-board Master Reference Oscillator (MRO).
The main firmware monitors the MRO PLL VCO control voltage using an A/D converter. The
MSI uses the measured voltage to determine a second control voltage to be applied to the PLL
that follows the MRO PLL VOC control voltage. A D/A converter on the MSI generates the
output. As the VCO control voltage changes slowly with time, the D/A voltage tracks the VCO
voltage. If the 10 MHz reference input to the transmitter is removed, the tracking voltage is