4-6
Theory of Operation
Flash PROM
Two Intel 28F008-compatible 1MB PROMs (A24 and A25), are used.
From a hardware point of view, a flash PROM is the same as an EPROM in read
mode. To write to it, however, a programming voltage (Vpp) needs to be applied to
a pin. The 12V voltage is generated by a switching regulator (A26), controlled by a
logic level (_EPPP).
NVRAM
This chip is powered through the lithium battery (VCT) when power is off. The chip
select is held high through a pull-up resistor to VCT to avoid accidental overwriting
while power is off.
Interrupt
Controller
In order to keep compatibility with both 68k hardware and software, it is necessary
to use a chip that prioritizes several interrupt sources. This is done by a NEC chip,
an uPD71059. It scans eight interrupt pins and sends a unique interrupt to the
processor when a (non-masked) interrupt appears.
Interrupt levels are assigned the following:
level 0
(lowest priority) acquisition board
level 1
small peripherals, unused
level
2
RS232
level
3
GPIB
level 4
small peripherals and acquisition board, unused
level 5
real time clock
level 6
time base (acquisition board)
level 7
(highest priority) only for test purposes. Linked to level 2 for
debugging.
Floppy Controller
The floppy controller chip directly interfaces to a double or high-density disk drive.
The floppy controller has a digital 8-bit input/output register, which is used to read
several status lines from the drive (disk inserted, etc.).
In principle, the controller is able to provide an interrupt when accesses are
completed. As these accesses are performed in non-time critical paths of the
program, The interrupt line has been wired to the input register, so that the program
has to poll this register until the interrupt line goes active.
The controller has it’s own timebase, a 24MHz crystal.
Centronics
Both external and internal Centronics ports are write-only. The data get latched in a
74HCT374 register (A45 for internal Centronics, A55 for external).
Содержание LC564DL
Страница 12: ...x Table of Contents ...
Страница 18: ...2 4 General Information ...
Страница 46: ...4 22 Theory of Operation 4 6 2 Power Supply Block Diagram ...
Страница 59: ...Performance Verification 5 13 ...
Страница 70: ...5 24 Performance Verification ...
Страница 95: ...Performance Verification 5 49 ...
Страница 115: ...Performance Verification 5 69 ...
Страница 122: ...5 76 Performance Verification Figure 5 14 1MΩ Ω Ω Ω Rise time Equipment Setup ...
Страница 148: ...6 14 Maintenance 6 6 4 Fan Problem ...
Страница 149: ...6 6 5 Power Supply Voltages Problem Maintenance 6 15 ...
Страница 150: ...6 16 Maintenance 6 6 6 Display Problem ...
Страница 151: ...6 6 7 Front Panel Controls Do not Operate Maintenance 6 17 ...
Страница 152: ...6 18 Maintenance 6 6 8 Remote Control GPIB or RS232 Problem ...
Страница 153: ...6 6 9 Performance Verification Fails Maintenance 6 19 ...
Страница 154: ...6 20 Maintenance 6 6 10 Floppy Disk Drive Problem ...
Страница 155: ...6 6 11 Graphic Printer Problem Maintenance 6 21 ...
Страница 156: ...6 22 Maintenance 6 6 12 Centronics Problem ...
Страница 157: ...6 6 13 Hard Disk Drive Problem Maintenance 6 23 ...
Страница 158: ...6 24 Maintenance ...
Страница 181: ...Mechanical Parts 8 1 8 Mechanical Parts Figure 8 1 LC564DL Cabinet ...
Страница 182: ...8 2 Mechanical Parts Figure 8 2 LC564DL Chassis Assembly ...
Страница 184: ...8 4 Mechanical Parts Figure 8 3 Power Supply Installation ...
Страница 185: ...Mechanical Parts 8 5 Figure 8 4 Lower Cover Assembly ...
Страница 187: ...Mechanical Parts 8 7 Figure 8 5 Lower Cover Assembly with CKTRIG Option ...
Страница 188: ...8 8 Mechanical Parts Figure 8 6 Lower Cover ...
Страница 190: ...8 10 Mechanical Parts Figure 8 7 CKTRIG Option ...
Страница 191: ...Mechanical Parts 8 11 Figure 8 8 Rear Panel Assembly ...
Страница 193: ...Mechanical Parts 8 13 Figure 8 9 900079 Main Board Assembly ...
Страница 194: ...8 14 Mechanical Parts Figure 8 10 900079 Main Board Assembly ...
Страница 196: ...8 16 Mechanical Parts Figure 8 11 Upper Shield Assembly ...
Страница 197: ...Mechanical Parts 8 17 Figure 8 12 Front Frame Assembly ...
Страница 199: ...Mechanical Parts 8 19 Figure 8 13 Keypad Assembly ...
Страница 200: ...8 20 Mechanical Parts Figure 8 14 Fan Assembly ...
Страница 202: ...8 22 Mechanical Parts Figure 8 15 Graphic Printer Assembly ...
Страница 203: ...Mechanical Parts 8 23 Figure 8 16 Upper Cover Assembly ...
Страница 205: ...Mechanical Parts 8 25 Figure 8 17 Hard Disk Assembly ...
Страница 206: ...8 26 Mechanical Parts Figure 8 18 Centronics VGA Interface Assembly ...
Страница 207: ...Mechanical Parts 8 27 Figure 8 19 Floppy Disk Assembly ...
Страница 209: ...Mechanical Parts 8 29 Figure 8 20 LC564DL Dimensions ...
Страница 210: ...8 30 Mechanical Parts Figure 8 21 LC564DL Packaging ...