12.5 Panel Board Power Connections
Prometheus-LC requires only +5V for operation. The panel boad is simply a connector board and requires no power. Make sure that the power supply used has enough current capacity to drive your system. The Prometheus-LC CPU requires up to 1.1A. If you have a disk drive or other modules connected, you need additional power. In particular, many disk drives need extra current during startup. If your system fails to boot properly, or if disk accesses do not work properly, the first thing to check is the power supply voltage level. Many boot-up problems are caused simply by insufficient voltage due to excess current draw on the +5V supply.
The panel board has two external input power connectors, J11 and J13, to satisfy a variety of input power scenarios.
J11 is a circular jack with a 2.5mm post. This connector is intended for direct 5VDC +/-5% input from the Diamond Systems PS-5VUS-01 wall adapter or an equivalent supply. The polarity for the power connector is tip = +5V, ring = Ground.
J13 is a DB9 male connector with multiple input voltages and applications. If a latching connector is required, the DB9 can be used in place of the circular jack to provide +5VDC.
If multiple system voltages are required, for example +5V, -5V, +12V, and/or -12V, these voltages can be supplied through J13 as well. The +5V and +12V are controlled by the CPU’s ATX power circuit, while the -5V and -12V are connected directly to the PC/104 bus pins.
J13 can also be used with a DC/DC power supply, such as Diamond Systems’ Jupiter-MM modules, in applications where the supply voltage is different from the required +5V. In this scenario, the input voltage is fed to the DB9 and routed to the power supply with cable connected between the supply and connector J5 or J12 on the bottom side of the panel board.
J5 is used when the power is to be routed from the output of the power supply directly onto the PC/104 bus through the PC/104 bus connectors on the power supply. In this application use the 2-wire power cable no. 698011. This cable contains a blue positive wire and a black negative wire. Connect the blue wire to the + screw terminal on the JMM power supply input connector and connect the black wire to the – terminal. Either J4 or J5 on the JMM board may be used for the power connection.
J12 is used when the supply voltages are intended to be switched by the ATX circuit on Prometheus. In this application the input and output of the power supply are connected to J12. The +5V and +12V are controlled by the ATX function, while the -5V and -12V are connected directly to the PC/104 bus pins.
