39 lines
1.4 KiB
Markdown
39 lines
1.4 KiB
Markdown
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## EVT1a -> EVT1b Changes
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ECO001: XTAL pin 1 is not NC
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Description: The first pin of most XTALs needs to be floating (NC). This is in contrast to the MEMS oscillator which requires pin 1 be connected to pin 4.
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Action: Modify the schematic so that pin 1 of the crystal oscillator is NC.
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ECO002: SPI flash footprint is incorrectly sized
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Description: The footprint for the SPI flash is sized according to the lead lengths, but is not wide enough. As a result, this part cannot be assembled.
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Action: Increase the width of the pads in the footprint.
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ECO003: USB footprint is slightly too narrow
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Description: The USB footprint is slightly too narrow. As a result, it slides back and forth in the USB slot.
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Action: Widen up the USB pad by 0.1mm
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ECO004: USB board edge has too much clearance.
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Description: Because of the clearance on the edge of the PCB, it can rock back and forth. This, in combination with ECO003, means the PCB does not sit firmly in a USB slot.
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Action: Extend the edge of the PCB towards the USB slot by 0.2mm.
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ECO005: XTAL footprint is backwards
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Description: The XTAL footprint has pin 1 in the upper-right-corner. However, the picture in the datasheet is mirrored, so pin 1 should actually be in the lower-left corner with numbering proceeding anti-clockwise (as opposed to the picture, which has pin 1 in the upper-right corner with numbering proceeding clockwise).
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Action: Fix the footprint and redo wiring.
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