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sparkfun / SF32u4_boards

Support files for SparkFun's 32u4-based Arduino-compatible development boards.
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boards.txt contains incorrect information for Pro Micro 8Mhz #16

Closed CircuitSerialKiller closed 9 years ago

CircuitSerialKiller commented 9 years ago

This line is missing: promicro8.bootloader.tool=avrdude

efuse value is incorrect, the line should read: promicro8.bootloader.extended_fuses=0xcb

Also, 8 second delay in 8MHz bootloader does not work in bootloader code when grounding rst 2x quickly.

BrentWilkins commented 9 years ago

Added a definition for the bootloader tool. Thanks.

Unsure what is wrong with the extended fuses. We have them set to detect brownout at 2.0V, rather than your suggested 2.6V. Are we missing a case where this matters? We are leaving bits 4:7 their default value of 1 (Table 28.3 in datasheet) but they aren't used anyway.

We found the 8 second delay on boot to be annoying, so we reduced it to around 1 second. HIt reset sooner (immediately) on our boards.

CircuitSerialKiller commented 9 years ago

OK, yes the brown out detector value doesn't matter. Grounding reset twice rapidly is supposed to keep it it in the bootloader for 8 seconds, which it does not (at least when using the 8MHz bootloader) in this code. It seems to keep it in the bootloader slightly longer, but definitely not 8 seconds to provide enough time to for the bootloader be seen. Also, there's some documentation that appears to be missing on SparkFun's web site. The 1200 baud signal is supposed to reset and allow 8 seconds apparently. I'll probably have to try recompiling and increasing TIMEOUT_PERIOD and EXT_RESET_TIMEOUT_PERIOD