Delta Tau PMAC2A-PC/104 manual Base Board Hardware Setup, Clock Configuration Jumpers

PMAC2A PC104 Hardware Reference Manual

BASE BOARD HARDWARE SETUP

On the PMAC2 PC/104 baseboard, there are many jumpers (pairs of metal prongs) called E-points or W- points. Some have been shorted together; others have been left open. These jumpers customize the hardware features of the baseboard for a given application and must be setup appropriately. The following is an overview of the several jumpers grouped in appropriate categories. For a complete description of the jumper setup configuration, refer to the E-Point Descriptions section.

Clock Configuration Jumpers

E1: Servo and Phase Clock Direction Control – Jumper E1 should be OFF if the board is to use its own internally generated phase and servo clock signals. In this case, these signals are output on spare pins on the J8 RS-232 serial-port connector, where they can be used by other PMAC controllers set up to take external phase and servo clock signals.

Jumper E1 should be ON if the board is to use externally generated phase and servo clock signals brought in on the J8 RS-232 serial port connector. In this case, typically the clock signals are generated by another PMAC controller and output on its serial port connector.

If E1 is ON for external phase and clock signals, and these clock signals are not brought in on the serial port connector, the watchdog timer will trip almost immediately and shut down the board.

E2 and E4: CPU Frequency Control Jumpers – When the PMAC I46 I- variable is set to zero jumpers E2 and E4 on the base PMAC2A PC/104 board control the frequency at which the CPU will operate (or attempt to operate). Generally, this will be the highest frequency at which the CPU is rated to operate. Note that it is always possible to operate a CPU at a frequency lower than its maximum rating. While it may be possible to operate an individual processor at a frequency higher than its maximum rating, particularly at low ambient temperatures, performance cannot be guaranteed at such a setting, and this operation is done completely at the user’s own risk.

•If jumpers E2 and E4 are both OFF, the CPU will operate at a 40 MHz frequency.

•If E2 is ON and E4 is OFF, the CPU will operate at a 60 MHz frequency.

•If E2 is OFF and E4 is ON, the CPU will operate at an 80 MHz frequency.

If I46 is set to a value greater than 0, the operational frequency is set to 10MHz * (I46 + 1), regardless of the jumper setting. See the Software Setup section for details on this.

E8: Phase Clock Lines Output Enable – Jump pin 1 to 2 to enable the Phase clock line on the J8 connector. Remove jumper to disconnect the Phase clock line on the J8 connector.

E9: Servo Clock Lines Output Enable – Jump pin 1 to 2 to enable the Servo clock line on the J8 connector. Remove jumper to disconnect the Servo clock line on the J8 connector.

Board Reset Jumpers

E0: Forced Reset Control – Remove E0 for normal operation. Installing E0 forces PMAC to a reset state, and this configuration is for factory use only; the board will not operate with E0 installed.

E3: Re-Initialization on Reset Control – If E3 is OFF (default), PMAC executes a normal reset, loading active memory from the last saved configuration in non-volatile flash memory. If E3 is ON, PMAC re-initializes on reset, loading active memory with the factory default values.

E13: Firmware Load Jumper – If jumper E13 is ON during power-up/reset, the board comes up in bootstrap mode which permits the loading of new firmware into the flash-memory IC on the board. When the PMAC Executive program tries to establish communications with a board in this mode, it will detect automatically that the board is in bootstrap mode and ask what file to download as the new firmware.

Jumper E13 must be OFF during power-up/reset for the board to come up in normal operational mode.

Baseboard Hardware Setup 5