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preenfm2 and preenfm3 / Re: Stm32F4Discovery port
« on: July 23, 2020, 10:46:53 PM »
Hi Dominique,
My version was made with an OLED display too, and it definitely needs the diode between V+ and +5V. The Disco board pins couldn't give enough high level for the OLED control, so I lowered the V+ supply a bit with the diode. Another solution would be some level shifters between the Disco pins and the OLED control pins.
I checked Your OLED's datasheet and the minimum input high level is the same as my screen: 0.8*VDD. This means that You need at least 4V, but the disco outputs only provide somewhere around 3V. The diode in the power line causes minimal brightness decrease while the input high level comes quite close to the needed value.
Norbim
My version was made with an OLED display too, and it definitely needs the diode between V+ and +5V. The Disco board pins couldn't give enough high level for the OLED control, so I lowered the V+ supply a bit with the diode. Another solution would be some level shifters between the Disco pins and the OLED control pins.
I checked Your OLED's datasheet and the minimum input high level is the same as my screen: 0.8*VDD. This means that You need at least 4V, but the disco outputs only provide somewhere around 3V. The diode in the power line causes minimal brightness decrease while the input high level comes quite close to the needed value.
Norbim