ArduinoAm29F010

Changeset

22:9cb1a32f298b
2015-03-07 Paul Boddie raw files shortlog changelog graph Added Am29F010 CE# logic for the Advanced ROM Adaptor.
README.txt (file)
     1.1 --- a/README.txt	Fri Mar 06 01:02:18 2015 +0100
     1.2 +++ b/README.txt	Sat Mar 07 23:32:25 2015 +0100
     1.3 @@ -61,14 +61,26 @@
     1.4  low, an attempt to read from ROM #2 would be occurring, and thus A14 would be
     1.5  held high.
     1.6  
     1.7 -ROM #1 CS#  ROM #2 CS#  Am29F010 A14
     1.8 -----------  ----------  ------------
     1.9 -0           0           Not defined
    1.10 -0           1           0
    1.11 -1           0           1
    1.12 -1           1           Not defined
    1.13 +Meanwhile, the CS# signal for the two ROM sockets would need to be combined to
    1.14 +produce a resultant CE# signal for the Am29F010.
    1.15 +
    1.16 +ROM #1 CS#  ROM #2 CS#  Am29F010 A14    Am29F010 CE#
    1.17 +----------  ----------  ------------    ------------
    1.18 +0           0           Not defined     Not defined
    1.19 +0           1           0               0
    1.20 +1           0           1               0
    1.21 +1           1           Not defined     1
    1.22  
    1.23 -It might therefore be possible to connect A14 to ROM #1's CS# signal.
    1.24 +It might therefore be possible to connect A14 to ROM #1's CS# signal. And the
    1.25 +resultant CE# signal could be the product of an AND gate:
    1.26 +
    1.27 +Am29F010 CE# = ROM #1 CS# AND ROM #2 CS#
    1.28 +
    1.29 +ROM #1  ROM #2  74HC08  Am29F010
    1.30 +------  ------  ------  --------
    1.31 +CS#             1A      A14
    1.32 +        CS#     1B
    1.33 +                1Y      CE#
    1.34  
    1.35  Pins
    1.36  ====