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PSM-500/500L/500LT SCPC Satellite Modem
4.2.2 Onboard Processor Power-On Sequence and Diagnostics
The processor goes through the following sequence every time the modem is powered up.
1. Sets up the stack pointer and initializes the register bank;
2. Disables all interrupts;
3. All internal RAM and all external RAM is tested by writing to it and reading from it. If
any value does not work correctly, the initialization is halted and an endless loop is
entered putting out a square wave on ALARM LED;
4. The front panel is checked for presence.
5. Checks the Flash memory contents and calculates its checksum value. If the
checksum does not correspond to that in the ROM, the initialization is halted and an
endless loop is entered putting out a square wave on the ALARM LED;
6. The EEPROM is tested for specific flag bytes in its contents. If the flags are incorrect,
the EEPROM is assumed to be corrupted and is re-initialized with the factory
defaults, removing the current. A message is displayed on the front panel LCD.
7. Initializes all variables and internal components;
8. The standard or optional interfaces are interrogated for type and installed options.
9. Initializes the serial UARTs, A/D converter and internal timers, enabling these
interrupts in the process;
10. Begins operating its main loop program which responds to control inputs, monitors
and displays terminal and LED status, controls the modulator output, FEC, operating
modes, etc.
4.2.3 Built-in Lamp Test
4.2.3.1 Lamp Test
The Front Panel LEDs and LCD display backlight are tested. This is meant to be viewed by an
operator. During the 4 seconds of this test both alarm relays are forced off.
Eb/No, input level and offset frequency are all within limits. The internal BERT is used to verify no
errors or loss of sync.
4.3 Updating Modem Software
The PSM-500 modem software and firmware are held in flash memory and can be field upgraded
by several methods. The most common is to download newer software revisions via the Internet
and install from a Window's type USB capable PC using the modem's USB control port. If a USB
capable computer is not available software and firmware can be updated via the serial control
port, but this method is not recommended because of the large amount of firmware and the slow
serial connection.
We do occasionally add new features or correct operating procedures within the modem software
that might lead to problems. When the operating software changes the Revision number is
updated. Some changes may involve modification of the information or structure in the non-
volatile EEPROM storage.
The latest versions of firmware, instructions and PC compatible update programs are available
on the
www.datumsystems.com
before attempting the procedures below
PSM-500/500L/500LT - Rev. 0.91
web site, and should be checked for the latest instructions
Maintenance
Page 4-7
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