Intel 80L188EC, 80L186EB, 80L186EC, 80C186EB, 80C188EB, 80L188EB, 80C188EC Power Supply, E1 Jumper

INTEL 186 EB/EC EVALUATION BOARD USER’S MANUAL

3.5POWER SUPPLY

The power supply connects to J2 on the board schematic. Pin 1 must connect to +5 volts and pin 2 must connect to ground. The supply is then regulated to 3.3 volts by the on-board circuitry. The VCC for the board is controlled by jumper E1. When E1 is in the A–B position, V CC = 3.3 volts; when E1 is in the B–C position, V CC = 5.0 volts. VCC is converted to +12 volts for optional Flash programming voltage.

E1

A

B

C

A – B VCC = 3.3 volts

B – C VCC = 5.0 volts

A2607-01

Figure 3-3. E1 Jumper

The LCD display controller VCC pin connects directly to the 5 volt supply, not the VCC plane, allowing 5 volt operation only.

2

1

+5VDC - VCC

Ground - VSS

Figure 3-4. J2 Power Connector

The Maxim* MAX750 component at U6 (EC) or U7 (EB) is a current-mode DC-DC converter. This device takes the 5 volt supply and steps it down to 3.3 volts. This voltage output is always supplied to provide VCC for the processor, memory, and logic when selected at E1.

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