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    please can somebody help me, where in cpu to connect the keyboard (FPGA)

    Goodmorning
    please can comebody help me, where to connect the keyboard
    do you see here in this circuit keyboard cpu vga ram are togethere connected
    Click image for larger version. 

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    but here is not keyboard connect only cpu vga data mem, eeprom, so where i have to connect the keyboard to wich pins? do i have to connect to d_f_m, like in circuit one of what do i have to change to make work also with keyboard this circuits
    Click image for larger version. 

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    thanks....

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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    The two pics show 2 different implementations.
    The d_f_mem is a multiplexed input from <1> keyboard or char_ram(pic1) or <2> data_mem or eeprom.

    but here is not keyboard connect only cpu vga data mem, eeprom, so where i have to connect the keyboard to wich pins?
    I did not completely understand your question.
    Do you want to have a keyboard input (as in pic1) to be ADDITIONALLY implemented in pic2?
    In that case just use a 3:1 MUX instead of 2:1 MUX and your 3rd input will be the keyboard input system.
    FPGA enthusiast!



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    Quote Originally Posted by dpaul View Post
    The two pics show 2 different implementations.
    The d_f_mem is a multiplexed input from <1> keyboard or char_ram(pic1) or <2> data_mem or eeprom.


    I did not completely understand your question.
    Do you want to have a keyboard input (as in pic1) to be ADDITIONALLY implemented in pic2?
    In that case just use a 3:1 MUX instead of 2:1 MUX and your 3rd input will be the keyboard input system.
    hello
    yes you are right
    but i just dont know where to connect in CPU, i mean i have to connect to d_f_m right? nothing else to change and ONLY
    to use (MUX 3:1) where 1 eprom 2 data meme and 3 keyboard to connected in cpu to d_f_m? right?



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    For the data path, yes just use a 3:1 MUX. For the other signals, use as they should be connected. You have two connection diagrams, just merge them and get a combined one, where the connectivity of all signals are legal.
    FPGA enthusiast!



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    Quote Originally Posted by dpaul View Post
    For the data path, yes just use a 3:1 MUX. For the other signals, use as they should be connected. You have two connection diagrams, just merge them and get a combined one, where the connectivity of all signals are legal.
    OOH thank you a lotttttt
    greetings….



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    Quote Originally Posted by dpaul View Post
    For the data path, yes just use a 3:1 MUX. For the other signals, use as they should be connected. You have two connection diagrams, just merge them and get a combined one, where the connectivity of all signals are legal.
    sorry i did not understand so good the last message #4 because i was think in that in pic1 char_ram is connected to d_f_mem

    in pic 2 char_ram is connected to adress_font

    is this like this keyboard connect to d_f_mem, also data_mem and eprom,
    so we use 3:1 mux,
    when signals is from keyboard d_f_mem = keyboard or ascii(char ram)

    when signal is from data_mem or eprom d_f_mem = ascii(char ram) = data_mem or eprom
    Last edited by michael 1978; 28th August 2019 at 11:54. Reason: correct



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    i am reading the book COMPUTER PRINCIPLES AND DESIGN IN VERILOG HDL


    so like Exercises in chapter 14

    Design a computer system that contains a CPU, instruction memory, data memory, character
    RAM (text mode), font table, PS/2 keyboard interface, VGA interface, and an I2C controller
    with an I2C EEPROM, and develop a simple editor that deals with not only the standard keys
    but also the extended keys by referring to Figure 14.35 is pic2



    so it explain pic1 and pic2



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    hello
    can somebody help please i am think in and think in, i dont know i post #4 the told me to use 3:1 MUX, so now how to connect to char_ram
    to use 4:1 mux, of can you help me how signals to connect to make work PLEASE
    so here i use 3:1 MUX and 4:1 MUX
    pic 1
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    pic 2
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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    Apologies, I had missed the I2C module.
    So as there are now the keyboard, char_ram, data_mem and i2c so there are 4 data paths going in to the CPU. So use a 4:1 MUX in front of the d_f_mem input.
    FPGA enthusiast!



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    Quote Originally Posted by dpaul View Post
    Apologies, I had missed the I2C module.
    So as there are now the keyboard, char_ram, data_mem and i2c so there are 4 data paths going in to the CPU. So use a 4:1 MUX in front of the d_f_mem input.
    thanks for answer
    is correct circuit in pos #8 pic 2 ?

    - - - Updated - - -

    Quote Originally Posted by dpaul View Post
    Apologies, I had missed the I2C module.
    So as there are now the keyboard, char_ram, data_mem and i2c so there are 4 data paths going in to the CPU. So use a 4:1 MUX in front of the d_f_mem input.
    thank for answer
    may i ask you
    is correct circuit in post #8 pic 2



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    I am giving my comments solely on the basis of the diagrams you have posting, without understanding the functionality.
    I think the correct one is in post #8 pic 1 (so it is a 3:1 MUX again), because the data_out of the char_ram should be going to the display unit.
    FPGA enthusiast!



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    Quote Originally Posted by dpaul View Post
    I am giving my comments solely on the basis of the diagrams you have posting, without understanding the functionality.
    I think the correct one is in post #8 pic 1 (so it is a 3:1 MUX again), because the data_out of the char_ram should be going to the display unit.
    hello
    yes that is true, but data_out of char ram need data from somewhere for example keyboard ,ic2, data memory
    oh my god i dont know, i am also a beginner, but if he need from data from keyboard need first data of input keyboard to be stored in data_mem or direct like first
    example in begin post #post 1 from keyboard to char ram to display or may 2 from data_mem and direct to char ram(if it so why is not good pic 2)
    what do you think? how it should be?
    because
    i am reading that book, like exercise in book he say
    Design a computer system that contains a CPU, instruction memory, data memory, character
    RAM (text mode), font table, PS/2 keyboard interface, VGA interface, and an I2C controller
    with an I2C EEPROM


    cpu = d_f_mem is data load, d_t_mem store data to, io_rdn is i/o read, io_wrn is i/o write, wvram video ram write, m_adder memory adress, write data memory write,

    man how to do it, i am amater



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    Re: please can somebody help me, where in cpu to connect the keyboard (FPGA)

    Quote Originally Posted by dpaul View Post
    I am giving my comments solely on the basis of the diagrams you have posting, without understanding the functionality.
    I think the correct one is in post #8 pic 1 (so it is a 3:1 MUX again), because the data_out of the char_ram should be going to the display unit.
    i was study, you are right, me also i think data_out of char_ram must go to display
    but can you help me how to connect in orde data_mem and keyboard and ic2

    he show 2 example in begin post #1 in first example

    assign d_f_mem = io_rdn? ascii : keyboard data

    and second example in post #2
    assign d_f_mem = io_rdn? dm_out(i2c_eeprom, data memory data_mem) : d_out(ic2 eeprom)

    so now i dont kow how to combine 4 signals (i know how to make mux(3:1)



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