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12.
100-MHz SDRAM Failure
Problem:
Excessive ringing on SDCLK pin.
Implication:
SDRAM does not run at 100 MHz.
Workaround:
For 100-MHz SDRAM development, Intel recommends using Rev F of the DCPXA250 processor
card in addition to this workaround. Contact your local Intel representative for availability.
Add a resistor termination network at the end of the SDCLK1 clock line.
1. Locate C68 on the top of the BBPXA2xx development baseboard. Solder one end of a
100-ohm, 0805 resistor to the plus (+) side of C68. Point this 100-ohm, 0805 resistor straight
up.
2. Solder one end of a 470-ohm, 0805 resistor to the ground side of C68. Point the 470-ohm,
0805 resistor straight up.
3. Connect the open sides of both the 100-ohm and 470-ohm resistors together with a small
gauge rework-wire.
4. Connect this junction to U40, pin 44.
No Fix
Status:
Board Rev:
Rev A and B
14.
LCD Touch Screen Intermittently Fails
LCD screen is open to excessive noise disruption on the touch screen.
Problem:
Excessive noise disruption reduces LCD screen display quality. The touch screen may not work
Implication:
correctly.
Note: BBPXA2xx development baseboards received after December 2001 do not require this ECO. The
manufacturing process was changed to incorporate this ECO.
Fix this problem by covering the back light inverter with copper foil shielding tape to decrease the
Workaround:
electrical noise transferred to the LCD and Touch Screen.
Material Needed:
•
1-inch heat shrink tubing.
•
2-inch wide EMI Copper Foil Shielding Tape.
Procedure:
1. Disassemble the BBPXA2xx development baseboard touch screen enclosure.
2. Remove the back light inverter.
3. Cut a piece of heat shrink tubing (1"x3") and place over the inverter.
4. Heat the tubing until it collapses on the inverter.
5. Cut a 2"x5" piece of copper tape and place on clear plastic disk covering the inverter. The
adhesive side should face the plastic.
6. Cut a 2"x5" piece of copper tape and place on the black plastic disk under the inverter. The
adhesive side should face the back of the LCD metal enclosure.
7. Reassemble the touch screen enclosure.
DBPXA250 and DBPXA210 Development Platforms Specification Update
®
Intel
BBPXA2xx Development Baseboard
13
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