Users may connect any or all of these points to custom circuitry, keeping in
mind the pre-defined bit assignments shown in Table 2-2. Data present on
DB0-DB7 would have been written there by the same DTACK state
machine data transfer cycle that provided the LATCH pulse. See "DTACK"
for a discussion of the DTACK state machine operation.
See Chapter 3, "Using the HP E1399A" for additional information on using
the Control Register. Refer to the VXIbus Specification, Section C.2.1.1.2
for detailed information concerning Control Register implementation
restrictions.
DTACK, Interrupt,
and Control
An Interface IC (U6) provides the timing and control signals for standard
data transfer cycles and interrupt requests/acknowledgments. Hardware and
software reset signals, together with a card fail signal, have also been
implemented.
DTACK
The Data Transfer ACKnowledge (DTACK) circuitry is centered around
the Interface IC (U6). A state machine in this IC controls all read and write
data transfer cycles. Operation begins with the state machine in the idle
state. See Figure 2-11 for the following discussion. Table 2-10 lists the parts
for the DTACK circuitry.
Table 2-10. DTACK Circuitry Parts
Reference
Designator
HP Part Number
Description
U21C
U6
U5C
U20C,D,F
1820 4643
1820-6731
1820-4057
1820-4242
IC, 74HCT02N Quad 2-input NOR
IC, Interface (PAL)
IC, 74F38N Quad 2-input NAND Buffer
IC, 74HCT14 Hex Schmitt-Trig Invrtr
Figure 2-11. DTACK Circuitry
30 Configuring the HP E1399A
Chapter 2
Summary of Contents for E1399A
Page 6: ...Notes 6 HP E1399A Register Based Breadboard Module User s Manual ...
Page 8: ...8 HP E1399A Register Based Breadboard Module User s Manual ...
Page 11: ...Figure 1 1 Digital Backplane Interface Block Diagram Chapter 1 HP E1399A Introduction 11 ...
Page 14: ...14 HP E1399A Introduction Chapter 1 ...
Page 18: ...Figure 2 2 HP E1399A Dimensions 18 Configuring the HP E1399A Chapter 2 ...
Page 21: ...Figure 2 5 Terminal Module Installation Chapter 2 Configuring the HP E1399A 21 ...
Page 40: ...Figure 3 2 Timing for Reading the Status Register 40 Using the HP E1399A Chapter 3 ...
Page 43: ...Figure 3 4 Timing for Writing to the Control Register Chapter 3 Using the HP E1399A 43 ...
Page 45: ...Figure 3 5 Interrupt Timing Chapter 3 Using the HP E1399A 45 ...
Page 53: ...Appendix B HP E1399A Parts List Schematic 53 ...
Page 54: ...Figure B 1 HP E1399A Breadboard Schematic 1 of 2 54 HP E1399A Parts List Schematic Appendix B ...
Page 55: ...Figure B 1 HP E1399A Breadboard Schematic 2 of 2 Appendix B HP E1399A Parts List Schematic 55 ...
Page 56: ...56 HP E1399A Parts List Schematic Appendix B ...
