| ??? 10/14/09 17:21 Read: times |
#169708 - some points Responding to: ???'s previous message |
Ofcourse yes this is a massive consideration, however I am a little microncontroller illiterate, so perhaps you could help me here.
Critical operation: here it is the speed at which it responds to the driver requesting a gear change. there are h two inputs (flappy paddles) I was considering having some electronics that would generate an interrupt request signal here to make sure this is always done instantly. The outputs are then simply two control signals which are connected to the if speed is a consideration then go for the SILabs f12x/f13x running at 1 clock at 100MHz (100 times faster than "plain vanilla") Other outputs: Flashing LED to let me know the system is alive, so this only needs to change state twice a second, is that correct ? 0.5 HZ should be fine LCD screen I have read is fairly easy to incorporate, is this true? there is lots of "sample code" for character based LCDs Output to ignition pause request is simply a control signal of a square wave triggering the ECU to invoke some function that is programmed during the ECU mapping. once ignition (or such) is involved, you primary concern becomes EMI resistamnce. Other inputs: The only thing I do not know about yet is the input data from the ECU, I do know this is sent serially but the information I have requested from the manufacturer has not arrived. the F12x/F13x has UART/SPI/IIC/SMB hardware, get the info before selecting derivative ECU data: I am not datalogging it, And only plan to display the revs via LCD currently so perhaps you could comment on this suitability, I assumed it would involve seperating the data sent serially and simply displaying the data that I will have saved in the RAM memmory that corresponds to the revs? Or is this probably not how it would work? sounds reasonable Questions: What do you mean by different ratio of clocks to cycles? the original '51 used 12 clocks per 'cycle', many modern derivatives use less (6/4/2/1). A cycle is the unit counted as to the time an instruction takes. e.g. a 2 cycle instruction will take 1us in a 12 clcoker running at 24MHz, and will also take 1 us in a 2 clcoker running at 2 MHz. Do tell me if this asking a bit to much and the information is available elsewhere for me to read. cheers again guys. the amount does not matter the explicity of the questions do. as far as "getting to know the '51" there is no better document than "the bible. Erik here are the links to "the bible" Chapter 1 - 80C51 Family Architecture: http://www.nxp.com/acrobat_d...ARCH_1.pdf Chapter 2 - 80C51 Family Programmer's Guide and Instruction Set: http://www.nxp.com/acrobat_d...UIDE_1.pdf Chapter 3 - 80C51 Family Hardware Description: http://www.nxp.com/acrobat_d...WARE_1.pdf |
