T A B L E   O F   C O N T E N T S
                ---------------------------------



.cp4
 1. MULT/IO INTRODUCTION (revision 4)........................   1

.cp4
 2. MULT/IO ARCHITECTURE.....................................   2
.cp3
    2.1. GROUP SELECT PORT BASE+7............................   2
         2.1.1. FUNCTIONS OF THE GROUP SELECT PORT...........   3
         2.1.2. GROUP PORT ASSIGNMENTS.......................   4
.cp3
    2.2. SELECTING I/O PORT ADDRESS..........................   5
.cp3
    2.3. RAM AND EPROM-- GENERAL.............................   5
         2.3.1. ADDRESSING RAM AND EPROM.....................   5
         2.3.2. EXTENDED ADDRESSING..........................   7
         2.3.3. BANK SELECTION...............................   8
         2.3.4. PHANTOM .....................................   9

.cp4
 3. SERIAL PORTS.............................................  11
.cp3
    3.1. CONFIGURING SERIAL CONNECTORS.......................  12
.cp3
    3.2. PROGRAMMING THE 8250................................  14
         3.2.1. BAUD RATE....................................  14
.cp3
    3.3. INITIALIZATION......................................  15
         3.3.1. SAMPLE SERIAL I/O ROUTINES...................  16
.cp3
    3.4. SERIAL DEVICE INTERRUPTS............................  18
         3.4.1. ACE INTERRUPT PROGRAMMING....................  19

.cp4
 4. PARALLEL DAISY-WHEEL PRINTER PORT........................  20
.cp3
    4.1. PARALLEL PORT DESCRIPTION...........................  20
.cp3
    4.2. PROGRAMMING THE DAISY PORT..........................  22
         4.2.1. GENERATING AN OUTPUT STROBE..................  23
         4.2.2. THE DAISY PORT AND INTERRUPTS................  23

.cp4
 5. REAL TIME CLOCK:  THE 1990...............................  24
.cp3
    5.1. 1990 ARCHICTECTURE..................................  24
         5.1.1. THE CLOCK PORT...............................  24
         5.1.2. CLOCK COMMANDS...............................  25
         5.1.3. PROGRAMMING THE CLOCK:  INTIALIZATION........  25
         5.1.4. PROGRAMMING THE 1990 CLOCK:  SETTING THE TIME  26
         5.1.5. PROGRAMMING THE 1990:  READING THE TIME......  27
         5.1.6. FORMAT OF THE 1990 TIME......................  27
         5.1.7. CALENDAR CLOCK IDIOSYNCRACIES................  28
         5.1.8. TIMING CONSTRAINTS...........................  29
         5.1.9. THE TIMED INTERRUPT GENERATOR................  29
         5.1.10. CLEARING CLOCK INTERRUPTS...................  29

.cp4
 6. INTERRUPT SYSTEMS........................................  29
.cp3
    6.1. INTERRUPT REQUIREMENTS..............................  30
.cp3
    6.2. PROGRAMMABLE INTERRUPT CONTROLLER (PIC).............  30
         6.2.1. PIC INTERRUPT VECTORS........................  31
.cp3
    6.3. PRIORITY MODES OF THE PIC...........................  31
         6.3.1. POLLED MODE..................................  32
         6.3.2. NESTED MODE..................................  32
         6.3.3. FULLY NESTED MODE............................  33
         6.3.4. ROTATING PRIORITY - MODE A...................  33
         6.3.5. ROTATING PRIORITY - MODE B...................  33
         6.3.6. SPECIAL MASK MODE............................  34
.cp3
    6.4. 
PIC STATUS REGISTERS................................  34
         6.4.1. INTERRUPT MASK REGISTER (IMR)................  34
         6.4.2. IN-SERVICE REGISTER (ISR)....................  34
         6.4.3. INTERRUPT REQUEST REGISTER (IRR).............  34
.cp3
    6.5. OTHER PROGRAMMABLE FEATURES.........................  35
         6.5.1. TRIGGERED MODES..............................  35
         6.5.2. BUFFERED MODE................................  35
         6.5.3. CALL ADDRESS INTERVAL (ADI)..................  35
         6.5.4. MICRO-PROCESSOR MODE.........................  35
.cp3
    6.6. CASCADING PIC'S.....................................  36
         6.6.1. MASTER/SLAVE MODE............................  36
.cp3
    6.7. AUTOMATIC END OF INTERRUPT MODE.....................  36

.cp4
 7. PROGRAMMING THE 8259-A PIC...............................  37
.cp3
    7.1. INITIALIZING THE PIC................................  37
         7.1.1. INITIALIZATION CONTROL WORDS 1 AND 2.........  37
         7.1.2. INITIALIZATION CONTROL WORD 3 (ICW3).........  39
         7.1.3. INITIALIZATION CONTROL WORD 4 (ICW4).........  40
.cp3
    7.2. OPERATION CONTROL REGISTERS.........................  41
         7.2.1. OPERATION CONTROL WORD 1 (OCW1)..............  41
         7.2.2. OPERATION CONTROL WORD 2 (OCW2)..............  41
         7.2.3. OPERATION CONTROL WORD 3 (OCW3)..............  42
.cp3
    7.3. SERVICE ROUTINE REQUIREMENTS........................  43

.cp4
 8. CONFIGURING THE MULT/IO FOR THE PIC......................  45
.cp3
    8.1. PIC IN POLLED MODE..................................  45
.cp3
    8.2. PIC AS MASTER.......................................  45
.cp3
    8.3. PIC AS SLAVE........................................  45
         8.3.1. CASCADE CABLE................................  45

.cp4
 9. MULT/IO REV. 4 PARTS LIST................................  48
.pa
                  L I S T   O F   F I G U R E S
                  -----------------------------



.cp3
 3-1: P1-P3 Connector Pinout.................................  12
 3-2: SERIAL CONFIGURATION JUMPERS...........................  12

.cp3
 4-1: DAISY PORT P4 CONNECTOR PINOUTS........................  22

.cp3
 5-1: TIME FORMAT EXAMPLE....................................  27
 5-2: 1990 INTERNAL CLOCK FORMAT.............................  28

.cp3
 8-1: CASCADE CABLE CONNECTIONS (P5).........................  46
 8-2: FOUR MULT/IO BOARDS IN MASTER/SLAVE CONFIGURATION......  47
.pa
                   L I S T   O F   T A B L E S
                   ---------------------------



.cp3
 2-1: GROUP SELECT PORT BASE+7...............................   3
 2-2: GROUP SELECT BITS......................................   3
 2-3: GROUP 0................................................   4
 2-4: GROUPS 1, 2, & 3.......................................   4
 2-5: MEMORY ADDRESSING......................................   6
 2-6: EXTENDED ADDRESSING....................................   7
 2-7: BANK SELECT AND SWITCH 10B-2...........................   8

.cp3
 3-1: ACE I/O GROUP DESCRIPTION..............................  11
 3-2: ACE JUMPER CONNECTIONS.................................  13
 3-3: REGISTERS OF THE 8250 ACE..............................  14
 3-4: DIVISOR LATCH CONSTANTS FOR STANDARD BAUD RATES........  15
 3-5: ACE INTERRUPT ASSIGNMENTS ON 8259 PIC..................  18

.cp3
 4-1: DAISY PORT SIGNALS AND I/O MAP.........................  21

.cp3
 5-1: 1990 CALENDAR/CLOCK I/O MAP............................  25
 5-2: CLOCK COMMANDS.........................................  25

.cp3
 6-1: MULT/IO CONNECTIONS TO THE PIC INTERRUPT REQUEST LINES.  31

.cp3
 7-1: EXAMPLE OF JUMP TABLES FOR SERVICE ROUTINES............  38
 7-2: INITIALIZATION CONTROL WORD 1 .........................  39
 7-3: INITIALIZATION CONTROL WORD 2..........................  39
 7-4: INITIALIZATION CONTROL WORD 3..........................  40
 7-5: INITIALIZATION CONTROL WORD 4 (ICW4)...................  40
 7-6: OPERATION CONTROL WORD 2...............................  42
 7-7: OCW2 COMMANDS (BITS 5 - 7).............................  42
 7-8: OPERATION CONTROL WORD 3 (OCW3)........................  43
³$:

    	2@8 2w   „ 
 7A   

  
    
    
 
   

 Y
CASCADE CABLE