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adafruit / Adafruit_HX8357_Library

Arduino library for HX8357
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How to increase SPI clock speed for HX8357? #24

Closed dsyleixa closed 5 years ago

dsyleixa commented 5 years ago

How to increase SPI clock speed for HX8357? The Graphics output is too slow for my purposes. I am using Arduino IDE 1.8.8 and the Feather M4 and the Feather ESP32 with this Featherwing HX8357 display.

ladyada commented 5 years ago

https://github.com/adafruit/Adafruit_HX8357_Library/blob/master/Adafruit_HX8357.cpp#L244

dsyleixa commented 5 years ago

Sorry, I don't understand: which faster values for (uint32_t freq) are valid? which freq are HX8357D or HX8357B? which is optionally even more faster (e.g. SPI clock 40MHz) ? Can I pass e.g. 40000000 for 40MHz or 60000000 for 60MHz?

ladyada commented 5 years ago

you can try any freq you like, technicall the chip has a max of 16000000 i think, but sometimes you can overclock

dsyleixa commented 5 years ago

if lower than 120MHz, must that be a freq of an integer clock divider (2,3,4,...) of the M4 cpu clock 120000000?

ladyada commented 5 years ago

Arduino picks the closest value yes

dsyleixa commented 5 years ago

ok, and now what do HX8357D or HX8357B stand for?

ladyada commented 5 years ago

hiya, we answered the question and we do not do tech support in github issues if you have tech support questions please post in the forums - this isn't a bug in the library you're asking about!