Rev1 Assembly Notes

Debug board

• F202 footprint appears to be too large for the fuse ordered (NANOSMDC050F/13.2-2)
• F201 is actually 1.1A, not 1.5A as the schematics indicate 
• Caps under Teensy (C316/C317) could use with being moved a bit
• U508/U509 package sucks ass
• C512/C511 should be further away from IC in -Y
• The indications for RESET and HALT are inverted (D401, D402) from what they should be
• Teensy USB port interferes with J302 with some USB cables
• Solder pads for DIN connectors could be slightly wider copper
• Logic probe connectors need more spacing in Y direction to fit the probes

CPU Board

• +12V fuse (F202) footprint is wrong
• Reset and NMI button logic is inverted from what it should be (lol)
  • U501 shouldn't be inverting type (use 74HC2G17 instead)
• D201 should be further set back (.3mm) from board edge
  • The H100 series LED seems to have a slightly different pin-to-front distance than the H201 double LED indicators
• 5V Analog caps (C608, C609, C614) should be up more
• LED current limiting resistors are out of whack
  • Lower the current limiting resistors for right angle LED indicators (needs more current)
  • Increase the current limiting resistors for two bonus debug LEDs (needs less current)
• Read/modify/write cycles may not work right
  • We need to deassert /DTACK when both /LDS and /UDS get deasserted
    
    • Neither of the byte strobes are on U102, which is responsible for generating /DTACK
    • May be able to bodge these into the GAL, since there’s a few spare inputs
  • Also, the /BERR timer and peripheral waitstate generator are reset by /AS
    • Probably a non issue since RAM is going to be 0 waitstate, and we can say CPU board peripherals don’t support read-modify-write (maybe only an issue for NVRAM)
• UART B (J503) should be centered between LEDs and UART A jack