8››                       P1050 MODIFICATION  1200XL SECTION    8-10-86       BY BOB WOOLLEY   75126,3446›››››         +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+ ›      ___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|___=_|_   ›     |  40 |  39 |  38 |  37 |  36 |  35 |  34 |  33 |  32 |  31 |  30 |  29 |  28 |  27 |  26 |  25 |  24 |  23 |  22 |  21 | |  ›     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     | |  ›     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     | |  ›     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     | |  ›     >     |     |     |     |     |     |   THIS IS NOT AN IC - IT IS A PLUG INTO U23   |     |     |     |     |     |     | |  ›     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     | |  ›     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     | |  ›     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     | |  ›     |___1_|___2_|___3_|___4_|___5_|___6_|___7_|___8_|___9_|__10_|__11_|__12_|__13_|__14_|__15_|__16_|__17_|__18_|__19_|__20_|_|  ›         = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |   = |    ›       +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ |    ›       |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   |    ›       |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   |    ›       |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   |    ›       |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   |    ›       |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   |    ›       |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   |    ›       | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+    ›      _|_=___|_=___|_=___|_=___|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=_|_|_=___|_=_|_|_=_|_   ›     | |40   |39   |38   |37   |36 | |35 | |34 | |33 | |32 | |31 | |30 | |29 | |28 | |27 | |26 | |25 | |24 | |23   |22 | |21 | |  ›     | |     |     |     |     |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |     |   | |   | |  ›     | |     |     |     |     |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |     |   | |   | |  ›     | |     |     |     |     |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |     |   | |   | |  ›     > |     |     |     |     |   | |   | |   | | THIS IS THE OLD U23 IC THAT HAS BEEN MOVED  | |   | |   | |     |   | |   | |  ›     | |     |     |     |     |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |     |   | |   | |  ›     | |     |     |     |     |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |     |   | |   | |  ›     | |     |     |     |     |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |   | |     |   | |   | |  ›     |_|_1___|_2___|_3___|_4___|_5_|_|_6_|_|_7_|_|_8_|_|_9_|_|10_|_|11_|_|12_|_|13_|_|14_|_|15_|_|16_|_|17_|_|18___|19_|_|20_|_|  ›       | =   | =   | =   | =   | = | | = | | = | | = | | = | | = | | = | | = | | = | | = | | = | | = | | = | | =   | = | | = |    ›       +-+   +-+   +-+   +-+   +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+ | +-+   +-+ | +-+ |    ›       |                           |     |     |     |     |     |     |     |     |     |     |     |     |           | |   |    ›       |                           |     |     |     |     |     |     |     |     |     |     |     |     |           | |   |    ›       |                           |     |     |     |     |     |     |     |     |     |     |     |     |           | |   |    ›       |                           |     |     |     |     |     |     |     |     |     |     |     |     |           | |   |    ›       |                           |     |     |     |     |     |     |     |     |     |     |     |     |           | |   |    ›       |                           |     |     |     |     |     |     |     |     |     |     |     |     |           | |   |    ›       |                           |     |     |     |     |     |     |     |     |     |     |     |     | D7SEL     | |   |    ›       |                           |     |     |     |     |     |     |     |     |     |     |     |     |   *       | |   |    ›       | +-+   +-+               +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   +-+   |     +-+ | +-+    ›      _|_=_|___=_|___=_____=_____=_____=_____=_____=_____=_____=_____=_____=_____=_____=_____=_____=_____=_____=_____=___|_=___   ›     | |40 |  39 |  38    37    36    35    34    33    32    31    30    29    28    27    26    25    24    23    22   |21   |  ›     | |CA1|  CA2|  IRQA  IRQB  RS0   RS1   RES   D0    D1    D2    D3    D4    D5    D6    D7   CLK2   CS0   CS2   CS1  |R/W  |  ›     | |   |     |                                                                                                       |     |  ›     | |   |     |                                                                                                       |     |  ›     > |   |     |                                 IC TYPE  6520   SAME AS U23 PIO                                       |     |  ›     | |   |     |                                                                                                       |     |  ›     | |   |     |                                                                                                       |     |  ›     | |GND|  PA0|  PA1   PA2   PA3   PA4   PA5   PA6   PA7   PB0   PB1   PB2   PB3   PB4   PB5   PB6   PB7   CB1   CB2  |+5v  |  ›     |_|_1_|___2_|___3_____4_____5_____6_____7_____8_____9____10____11____12____13____14____15____16____17____18____19___|20___|  ›       | = |   = |   =     =     =     =     =     =     =     =     =     =     =     =     =     =     =     =     =   | =      ›       +-+ |   | |   |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |   +-+      ›       |   |   | |   |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |            ›       |   |   | |   |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |            ›       |   |   | |   |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |            ›       |   |   | |   |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |            ›       |   |   | |   |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |            ›       |   |   | |   |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |     |            ›       *   *   * *   *     *     *     *     *     *     *     *     *     *     *     *     *     *     *     *     *            ›                                                                                                                                  ›       ---------------------------  THIS IS A 25 (OR 50) PIN FLAT CABLE FROM THE 1200XL TO THE 1050  -----------------            ›                                                                                                                                  ›                                                                                                                                  ›                                                                                                                                  ›                  D7SEL - WIRE TO PIN 7 OF U18 (74LS138). ››››››››››››››››››››››››››››››››››››››››››››››››››››››››››››