CG-1280 Rev. N 09/13 - General Dynamics SATCOM Technologies

Overview2.4.1.1 VertexRSI Central Processing Unit (VCPU) PCB AssemblyThe 7200 ACU uses the Motorola 68030 32-bit microprocessor as the CentralProcessing Unit (CPU), providing sufficient computing power for the sophisticatedcontrol and tracking algorithms used by the ACU. A dedicated VME CPU circuitcard is provided, which includes the CPU, Read-Only Memory (ROM), RandomAccess Memory (RAM), bus control circuitry, and nonvolatile memory controlcircuitry, providing efficient and reliable system operation.The VCPU card has several indicators and switches mounted on the VME frontpanel to provide the user with basic diagnostic information.Figure 2-6VCPU CardD1 Halt LED – This bi-color green/red LED indicates the operational status of the68030 CPU. If this LED is red the processor is halted and the system will notoperate, consult the factory for assistance. This LED will always be illuminatedgreen even when the board is held in reset.D4 Reset LED – This bi-color green/red LED indicates the reset status of the board.If this LED is red it means the board is in reset. The following events can cause areset condition to occur:1) 2.5 VDC undervoltage fault – If this is the cause then LED D2 (SMT LEDlocated between the battery and the left hand side of the board) will beextinguished indicating that the 2.5V power supply source has fallen below2.38VDC. Check the voltage to ensure it is above 2.38VDC. Potentiometer PT1sets the threshold for this fault (Re-adjust per General Dynamics document CG-0283).2) 3.3 VDC undervoltage fault – If this is the cause the battery monitor IC (U1)has detected a voltage lower than 2.9 VDC. Check the 3.3V regulator output(VR1) to see if 3.3V is the output voltage.3) 5.0 VDC undervoltage fault – If this is the cause then LED D3 (SMT LEDlocated between the battery and the left hand side of the board) will beextinguished indicating that the 5.0V power supply source has fallen below4.75VDC. Check the voltage to ensure it is above 4.75VDC. PotentiometerPT2 sets the threshold for this fault (Re-adjust per General Dynamics documentCG-0283).4) Dip Switch S6 pos 6 in the ON position – Leaving this dip switch in the ONposition holds the board in reset; change the position of the switch to the OFFposition to allow the board to operate normally.2-9