RC 03 29 08

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  • Previous work on Friday verified that the bootloader on the ARM worked. Code was loaded to the ARM that flashes the lights.
  • Determined that the ARM-JTAG errors were due to some slightly undocumented errors in the reset circuitry. The JTAG circuitry checks that the level on RTCK is high as /RST is released. A capacitor was added across the reset pin to slow the rise time on /RST as its released.
  • Found that the internal pull-up on /TRST (PO.27 pin 8) is incredibly weak (0.7-0.5V). The result is that the JTAG circuitry is never pulled out of reset. This fix inverts the operation of WR which is also on that pin. From here on WR is now /WR.
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