Universal Bus Logging Card
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
AbstractThe universal bus logging device is a card which is intended to be used on a communication controller system as a monitoring device for universal bus data transfers instead of a logic analyzer.
Universal Bus Logging Card
The universal bus logging device is a card which is intended to be used on a communication controller system as a monitoring device for universal bus data transfers instead of a logic analyzer.
The logging card will record up to 1,014 "words" in four blocks of 256. The information "word" recorded consists of the 16 data bits, two parity bits, and 10 tags. Recording may be either on a time basis, using an external timing signal, or on a data transfer basis, using internal logic. This logic enables all data transfers, address/control field transfers and cycle steal control word (CSCW) transfers to be recorded.
Recording may be started or stopped on a combination of data transfer type and/or data pattern and/or external condition.
Information recorded may be displayed, one word at a time, on the display incorporated on the card. While the device is recording, the instantaneous status of the data bus and all 16 tags is displayed.
The card is comprised of five logical portions. These are:
- display and operator controls 1,
- input buffer 2,
- event detection 3,
- start/stop control 4, and
- memory and memory control 5.
The following sections describe these five areas.
In the display and operator controls block 1, the operator control consists of: a) record/replay switch,
b) step/reset switch,
c) condition select switch,
d) start and stop switches,
e) data compare switches, and
f) memory bank select switches.
The record/replay switch in the record position causes the bus data and tags to be recorded under the control of switches (b) to (f). In the replay position, the bank of memory selected by switch (f) is displayed one word at a time under the control of switch (b).
The record/replay switch being in the record position, the step/ reset switch performs its reset function. The memory address is set to zero, and, if the stop switch is on, recording will be started.
The record/replay switch being in the replay position, the step/ reset switch performs its step function. The memory address is incremented by one each time the switch is depressed.
The display comprises Tag display, Data display, and Control display.
The control display area consists of hexadecimal displays (HEX DPLY) and light-emitting diodes (LEDs) .
The hexadecimal displays indicate the memory location currently being addressed in the selected block. In replay mode this is the location whose contents are being displayed which indicates the memory location currently being written. The LEDs indicate the status of the logging card.
The Data display consists of four hexadecimal displays. In record mode the Data display indicates the current bus data. In replay mode the Data display indicates the data recorded at the memory location indicated on the Control display.
The Tag display consists of eight red LEDs and eight green LEDs. The red LEDs indicate tags originating at the central control unit of the controller, and the green LEDs, ta...