hello arduboy team,
Actually right now, i am doing the homemade Arduboy with flash chip enabled.Before it i have tried a lot but when i come to the CS pin of flash chip i found it hang to the RX pin of Atmega32u4, but when @bateske (sir*) did that arduboy mini he connect the CS pin to HWB/PE2 pin of atmega32u4. and also in my arduboy i want both RX and TX pin free for any USART/UART communication, So how Can i change the flash chip from CS pin to RX pin >> HWB/PE2 pin or any other pin? is it possible through software? Really i am very eagerly waiting for your replies.
Thanks arduboy team 
And also i need SDA and SCL pin for I2C communication so i want to use the CS pin of flash chip to HWB/PE2 pin !!
can any body help me?? really i want to know this i know it is possible but don’t know how to do it 
your help need very urgency please 
Yes, but you have to modify the bootloader. The mini will have the HWB/PE2 pin as the CS flash so that i2c is available.
@Mr.Blinky has made edits to compile the bootloader for the mini, and that should work for you I think. I don’t know if it’s been pushed to the github yet though?
I really get worried when people say Arduboy is urgent because it shouldn’t be 
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@Mr.Blinky sir can you explain about,
compile the bootloader for the for the mini
how can i use the cs pin of flash card to HWB/PE2 pin of atmega32u4 .
@Mr.Blinky sir is it published if it is then where i got and how can i use the bootloader please explain. please
I just dit 
Update the Home Made Package to 1.3.9 then select Arduboy mini when you flash the bootloader and compile sketches.
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@Mr.Blinky sir i updated the package into and there i got 1.3.9 but in the arduboy mini pakage we only got board, core, bootloader and there is no option for choosing display. I think here the default display is ssd1306 and i want to use homemade arduboy, i don’t have any official arduboy mini
so can i use “Homemade Arduboy” with flash select: “Port E2/HWB” ?
is there any circuit changes (only cs>> E2/HWB ) or any other changes??
and @Mr.Blinky sir my last question can we use flash chip (WE25Q128JVPQ smd/smt) directly 5v??
is it safe i think the flash chip will fry ?? @bateske sir also told we can use direct 5v or i should follow your diagram
and now also i will use CS pin to HWB/PE2 pin so is their any changes in the upper diagram or i should use 5v directly??
that schematic will work
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When you burn the bootloader you need to select Arduboy mini. That bootloader supports SSD1306 SSD1309 displays (SH1106 display will work too but there will be a 2 pixel shift) and work with Leonardo, Pro Micro Standard wiring (Arduino Micro wil work too but willl have inverted Rx Tx LEDs)
When compiling sketches you can use the homemade selection with any of your choices.
Yes @bateske and me didn’t encounter any problems powering the flash chip from 5V and you can follow the light schematic (but use HWB instead of RX/SDA) If you have doubts about powering the flash chip with 5V you can also power your homemade arduboy completely from 3.3V
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ok got it @bateske and what about external pullup resistor for I2C communication? I seen in the arduboy mini you have used two external pull up resistor what is the value of that resistor? what is the ideal value of resistor, for better I2C communication?
It entirely depends on the application. The Arduino uses internal pull ups by default with its wire library, and in my testing that has been sufficient. I have them on the mini mostly to make @mlxxxp happy that it correctly matches the Qwiic standard.
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Thank you @MLXXXp @bateske @Mr.Blinky actually i am working with the tiniest arduboy mini with all the communication(I2C,SPI,USART) …
its only 30mm*30mm. i did all the outer box prototype,but all the hardware will be deliver after 1-2 day then i will complete whole project.
but your help always be needed if i got any error or problem i will disturb you for sometime
.
thanks a lot to the arduboy community 
without you i can not complete this project…