ArduinoAm29F010

Changeset

0:1b3978439bdb
2015-01-18 Paul Boddie raw files shortlog changelog graph An initial design using four 74HC273 ICs: three for output, one for input.
README.txt (file)
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/README.txt	Sun Jan 18 00:37:55 2015 +0100
     1.3 @@ -0,0 +1,182 @@
     1.4 +Pins
     1.5 +====
     1.6 +
     1.7 +A0-A16      17-bit addressing
     1.8 +DQ0-DQ7     8-bit data transfer
     1.9 +CE#         chip enable
    1.10 +OE#         output enable
    1.11 +WE#         write enable
    1.12 +VCC         5V
    1.13 +VSS         ground
    1.14 +NC          (not connected)
    1.15 +
    1.16 +Low-Level Operations
    1.17 +====================
    1.18 +
    1.19 +CE# high            standby
    1.20 +CE# low             read, write or output disable
    1.21 +
    1.22 +OE# high, WE# high  output disable
    1.23 +OE# low, WE# high   read
    1.24 +OE# high, WE# low   write
    1.25 +
    1.26 +Thus, for reading and writing:
    1.27 +
    1.28 +OE# = not WE#
    1.29 +
    1.30 +Timing
    1.31 +======
    1.32 +
    1.33 +Addresses are latched on the falling edge of the latest of WE# and CE#
    1.34 +Data is latched on the rising edge of the latest of WE# and CE#
    1.35 +
    1.36 +Strategy:
    1.37 +
    1.38 + 1. Start with CE#, OE#, WE# high       (standby, output disable)
    1.39 + 2. Bring CE# low                       (output disable)
    1.40 + 3. Set addresses
    1.41 + 4. Bring WE# or OE# low for operation  (write or read)
    1.42 + 5. Read or write data
    1.43 + 6. Bring WE# or OE# high               (output disable)
    1.44 +
    1.45 +Operation Modes
    1.46 +===============
    1.47 +
    1.48 +By default, the device is in read mode, meaning that merely bringing OE# low
    1.49 +will produce data for the asserted address.
    1.50 +
    1.51 +To issue commands to change the mode involves write operations with specific
    1.52 +address and data arguments.
    1.53 +
    1.54 +Sectors
    1.55 +=======
    1.56 +
    1.57 +A[16...14] selects each 16KB sector.
    1.58 +
    1.59 +Commands
    1.60 +========
    1.61 +
    1.62 +Reset                       (A=$555; D=$AA); (A=$2AA; D=$55); (A=$555; D=$F0)
    1.63 +Autoselect (manufacturer)   (A=$555; D=$AA); (A=$2AA; D=$55); (A=$555; D=$90); (A=$X00; D=$XX)
    1.64 +                            => D=$01
    1.65 +Autoselect (device)         (A=$555; D=$AA); (A=$2AA; D=$55); (A=$555; D=$90); (A=$X01; D=$XX)
    1.66 +                            => D=$20
    1.67 +
    1.68 +Simple reset                (A=$XXX; D=$F0)
    1.69 +
    1.70 +Arduino Interfacing
    1.71 +===================
    1.72 +
    1.73 +Arduino can employ at most 14 digital pins, whereas the Am29F010B requires 17
    1.74 +address pins, 8 data pins, plus 3 control pins to be utilised.
    1.75 +
    1.76 +One solution is to map the 3 control pins directly to the Arduino, then to
    1.77 +channel address and data via 8 common pins to latches, and then employ the
    1.78 +remaining pins to control the latches.
    1.79 +
    1.80 +Two pins can be used to select the latches:
    1.81 +
    1.82 +Pin A   Pin B   Latch select
    1.83 +-----   -----   ------------
    1.84 +0       0       0
    1.85 +0       1       1
    1.86 +1       0       2
    1.87 +1       1       3
    1.88 +
    1.89 +Thus, the following logic is required:
    1.90 +
    1.91 +CP (latch 1) = ~A & B
    1.92 +CP (latch 2) = A & ~B
    1.93 +CP (latch 3) = A & B
    1.94 +CP (latch 0) = ~A & ~B
    1.95 +
    1.96 +Selector (in)   74HC04 (NOT)    74HC08 (AND)    Selector (out)
    1.97 +-------------   ------------    ------------    --------------
    1.98 +A               1A (*)
    1.99 +                1Y              1A 4A
   1.100 +B                               1B (*)
   1.101 +                                1Y              LS1
   1.102 +A                               2A (*)
   1.103 +B               2A (*)
   1.104 +                2Y              2B 4B
   1.105 +                                2Y              LS2
   1.106 +A                               3A (*)
   1.107 +B                               3B (*)
   1.108 +                                3Y              LS3
   1.109 +                                   4Y           LS0
   1.110 +
   1.111 +(*) Apply pull-down resistor to 74HC04 1A, 2A, 3A, 3B when driving using switches.
   1.112 +
   1.113 +As a result, only 13 pins are needed on the Arduino.
   1.114 +
   1.115 +Arduino     Selector    74HC273 #1  74HC273 #2  74HC273 #3  74HC273 #0  Am29F010B
   1.116 +-------     --------    ----------  ----------  ----------  ----------  ---------
   1.117 +1                                                                       CE#
   1.118 +2                                                                       OE#
   1.119 +3                                                                       WE#
   1.120 +4           A
   1.121 +5           B
   1.122 +            LS1         CP
   1.123 +            LS2                     CP
   1.124 +            LS3                                 CP
   1.125 +            LS0                                             CP
   1.126 +6                       D0 (*)      D0 (*)      D0 (*)      Q0
   1.127 +7                       D1 (*)      D1 (*)      D1 (*)      Q1
   1.128 +8                       D2 (*)      D2 (*)      D2 (*)      Q2
   1.129 +9                       D3 (*)      D3 (*)      D3 (*)      Q3
   1.130 +10                      D4 (*)      D4 (*)      D4 (*)      Q4
   1.131 +11                      D5 (*)      D5 (*)      D5 (*)      Q5
   1.132 +12                      D6 (*)      D6 (*)      D6 (*)      Q6
   1.133 +13                      D7 (*)      D7 (*)      D7 (*)      Q7
   1.134 +                        Q0                                              A0
   1.135 +                        Q1                                              A1
   1.136 +                        Q2                                              A2
   1.137 +                        Q3                                              A3
   1.138 +                        Q4                                              A4
   1.139 +                        Q5                                              A5
   1.140 +                        Q6                                              A6
   1.141 +                        Q7                                              A7
   1.142 +                                    Q0                                  A8
   1.143 +                                    Q1                                  A9
   1.144 +                                    Q2                                  A10
   1.145 +                                    Q3                                  A11
   1.146 +                                    Q4                                  A12
   1.147 +                                    Q5                                  A13
   1.148 +                                    Q6                                  A14
   1.149 +                                    Q7                                  A15
   1.150 +GND                                                                     A16 (not used)
   1.151 +                                                Q0          D0 (*)      DQ0
   1.152 +                                                Q1          D1 (*)      DQ1
   1.153 +                                                Q2          D2 (*)      DQ2
   1.154 +                                                Q3          D3 (*)      DQ3
   1.155 +                                                Q4          D4 (*)      DQ4
   1.156 +                                                Q5          D5 (*)      DQ5
   1.157 +                                                Q6          D6 (*)      DQ6
   1.158 +                                                Q7          D7 (*)      DQ7
   1.159 +5V                      MR# (**)    MR# (**)    MR# (**)    MR# (**)
   1.160 +5V          VCC         VCC         VCC         VCC         VCC
   1.161 +GND                                                         VSS
   1.162 +
   1.163 +(*) Apply pull-down resistor to 74HC273 D inputs when driving using switches.
   1.164 +(**) Apply pull-up resistor to 74HC273 MR# inputs to preserve state.
   1.165 +
   1.166 +74HC273 Q outputs may initially be high and should be reset, either driving
   1.167 +MR# low or by explicitly latching values onto each device.
   1.168 +
   1.169 +Set Address
   1.170 +-----------
   1.171 +
   1.172 +Selector A = 0; Selector B = 1; 74HC273 #1 D[7...0] = A[7...0]
   1.173 +Selector A = 1; Selector B = 0; 74HC273 #2 D[7...0] = A[15...8]
   1.174 +
   1.175 +Write Data
   1.176 +----------
   1.177 +
   1.178 +Configure pins as D[7...0]
   1.179 +Selector A = 1; Selector B = 1; 74HC273 #3 D[7...0] = D[7...0]
   1.180 +
   1.181 +Read Data
   1.182 +---------
   1.183 +
   1.184 +Configure pins as Q[7...0]
   1.185 +Selector A = 0; Selector B = 0; Q[7...0] = 74HC273 #0 Q[7...0]