what does it mean 4 bit counter, 4 bit memory

Discussion in 'General Electronics Chat' started by vead, Dec 29, 2013.

  1. vead

    Thread Starter Active Member

    Nov 24, 2011
    621
    8
    I am little bit confused here
    what does it mean 4 bit counter how many event it may be count
    4 bit ram how many bit it may be store
     
  2. ScottWang

    Moderator

    Aug 23, 2012
    4,850
    767
    4 bits counter that it will count as below:

    4 bits counter
    Code ( (Unknown Language)):
    1.  
    2. Num b3 b2 b1 b0
    3. ----------------------
    4.   0      0   0   0   0
    5.   1      0   0   0   1
    6.   2      0   0   1   0
    7.   3      0   0   1   1
    8.   4      0   1   0   0
    9.   5      0   1   0   1
    10.   6      0   1   1   0
    11.   7      0   1   1   1
    12.   8      1   0   0   0
    13.   9      1   0   0   1
    14.   a      1   0   1   0
    15.   b      1   0   1   1
    16.   c      1   1   0   0
    17.   d      1   1   0   1
    18.   e      1   1   1   0
    19.   f       1   1   1   1
    20.  
    4 bit ram as 74LS89 - 64-Bits Random Access Memory(Open Collector).
    It has 4 bits x 16 = 64 bits memory cell to store the 4 bits and 16 words of datas.
     
    Last edited: Dec 29, 2013
  3. vead

    Thread Starter Active Member

    Nov 24, 2011
    621
    8
    thanks for reply
    4 bit counter 2*2*2*2=16 possible combinations it can count 16 events
    4 bit ram what does it mean 4X16
     
  4. ScottWang

    Moderator

    Aug 23, 2012
    4,850
    767
    The digital number counting with parallel as:
    1 pin - 1 bit
    4 pins - 4 bits
    8 pins - 8 bits = = 1 byte
    4 bits = 1 nibble
    4 bits = 1/2 byte(half byte)
    2 bytes = 1 word
    so 4 bits = 1/2 byte = 1 bibble

    The meaning of 4 x 16 is discribe the memory has 4 bits and 16 positions to store, so 4 bits x 16 = 64 bits.
     
    Last edited: Dec 29, 2013
  5. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,377
    494
    In this specific case it means that you have a table. The table has 16 rows, 4 columns. The 4 columns represent the 4 bits. Each cell of the table can hold one bit. A whole row will hold 4 bits.
     
  6. vead

    Thread Starter Active Member

    Nov 24, 2011
    621
    8


    what is memory location i think 64 is memory location to store 4 bit data
     
  7. ScottWang

    Moderator

    Aug 23, 2012
    4,850
    767
    Go to check the internal structure of 74LS89 carefully on page 2 of #2.

    There are 4 positions for 4 bits, 64 positions for 64 bits.

    That is just like the LED dot matrix, whatever you like to say as 4 rows and 16 columns or 4 columns and 16 rows.
     
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