good day to all of you, now then i wanted to ask for some help with displaying multiple numbers on a 7 segment display, some context; for a univerisity project i am required to code absolutely everything in c only; we are not allowed to use any arduino functions whatsoever; so that means the use of anything from the functions section on the resources page is completely prohibited and we get 0 marks right off the bat. anyway back on topic i am using a arduino mega 2560 and i wanted to display the numbers 1-16, i was wondering how i would do that with a double 7 segment display with c only; i did some searching around on here and the best i could find was this thread;https://forum.arduino.cc/index.php?topic=371999.0 but i saw it was a bit dated so i felt it was best to start a new thread than revive that older thread considering.
i haven't starting coding it just yet however i can supply some details; the double 7 segment is a ACD8143 one, it has 14 pins and can display in RGB (pretty fancy for the first one i found and brought if i am being honest) here is a link to the data sheet;http://www.adh-tech.com.tw/files/ACD8143.pdf i have successfully got it displaying using a battery only so i know it works but now i want to take it a step further so i was thinking of wiring with the common cathodes of each respective 7 segment to their own pins drawing low (cathode needs to be grounded for the leds to work) so 4,7,8 going to pin 23 and 10, 11, 14 going to pin 22, the remaining 8 control the seven segments and the decimal points, they have been wiring in order of A to DP following the datasheet from pin 2 to pin 9.
now for the questions; (a) in particular i read on the previous one that a limiting resistor needs to be used, can i ask about a recommendation for the a minimum rated resistor? (b) i read that it is impossible to display two separate numbers at the exact same time on the device i have can i ask as to how i would go about multiplexing it instead in c only? finally (c) can i ask how i would go about activating the fast pwm mode in c only code for pins 2 - 9? if i can do that i can use it to set the intensity of the leds so knowing would be a huge help as deciphering the arduino mega 2560 datasheet is painful a task indeed.
sorry about all the questions and/or if i am asking in the wrong area i really appreciate any and all contribution made to this in order to help me out even if it is to nudge me in the right direction :)