Datasheet

7–211
TFB2002
I/O Controller
TFB2022
64-Bit
Data-Path
Unit
TFB2010
Arbitrator
FB2031* FB2031* FB2031* FB2031*
FB2040
FB2031*
FB2032 FB2040*
25-mm Stub Length MAX
Address/Data Status Command Arbitration Sync
Connector
NOTE: The second-part type descriptor (*) indicates that a second transceiver is mounted on the opposite side of the board.
Figure 3. Uncached 64-Bit Futurebus Layout With Texas Instruments Controller Chipset
and Today’s Most Integrated Transceivers
Another problem with the present generation of transceivers is the purchasing requirement for multiple transceiver types.
Continuing with the above example, the common 64-bit uncached solution requires three different transceiver types for a
complete distributed arbitration Futurebus implementation (see Table 2).
Table 2. Transceiver Descriptions for 64-Bit Uncached Futurebus Boards
Using FB20xx Series Transceivers
DEVICE DESCRIPTION
QUANTITY
PER
BOARD
FB2031 9-Bit Data/Address Transceiver With Clock and Latch 9
FB2032
†
Arbitration Contest Transceiver 1
FB2040 8-Bit Status/Sync Transceiver With Split TTL I/O 3
Total Part Count 13
†
Optional for distributed arbitration only
These transceivers were designed quite differently from one another due to the specific functions they perform in the system
(data/address, sync, arbitration, status, or command). Figure 4 highlights the functional differences between the FB2040 (status
and sync transceiver) and the FB2031 (address/data transceiver). The main distinctions are the universal storage modes
(transparent, latched, or clocked) of the FB2031 and the separate, or split, TTL I/O pins of the FB2040. As previously noted, until
recently, efforts to develop any sort of true universal BTL/Futurebus transceiver have not been practical due to the absence of
a viable, high-power, fine-pitch package with more than 56 pins.