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dbuezas / lgt8fx

Board Package for Logic Green LGT8F328P LGT8F328D and LGT8F88D
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LGT ISP: cap or 5v short of reset pin unnecessary? #319

Open dbuezas opened 1 month ago

dbuezas commented 1 month ago

I accidentally discovered that uploading as ISP still works without inhibiting reset on the programmer. It just takes 2 seconds longer to start (since I left the bootloader in my programmer).

I'm considering to remove the extra step of adding a cap to rst (or the dangerous hack of shorting it to 5v) from the ISP guide , or at least to mark it as optional.

Any thoughts on this?

LaZsolt commented 1 month ago

LGT ISP: cap or 5v short of reset pin unnecessary?

Normally not necessary to connect the reset pin neither in the LGT ISP nor in the device you want to program. I regularly uploaded program via LGT ISP without connected reset pin. In my opinion, the idea to use the capacitor or pull up the LGT ISP reset pin to 5V was to not have to use a different connection than usual between USB-serial and LGT ISP.

Anyway, if SWD, SWC used as I/O port, in the device you want to program, then reset pin must be connected to LGT ISP.

dbuezas commented 1 month ago

I mean the reset pin of the ISP (not the chip being programmed). When one uploads the programmer will reset unless its reset pin isn't forced high, but it still uploads afterwards.