DM9081FP DAVICOM [Davicom Semiconductor, Inc.], DM9081FP Datasheet - Page 8

• Manufacturer Part Number: DM9081FP
• Description: 10BASE-T Hub Controller
• Manufacturer: DAVICOM [Davicom Semiconductor, Inc.]

External Logic
A simple logic scheme is required when more than
two DM9081 chips are connected to increase the
total number of repeater ports. The external logic
should have one input (EXPOUT#) and one output
The above equations are in positive logic, i.e., a
variable is true when asserted. An example of three
banked DM9081 chips is shown in Figure 1. The
cascade IC number recommended: under 3 and
inclusive.
8
EXPIN1# =
EXPIN2# =
EXPIN3# =
EXPINn# =
.
.
.
Figure 1. Multiple DM9081 Devices
EXPOUT2# & EXPOUT3# &
EXPOUT1# & EXPOUT3# &
EXPOUT1# & EXPOUT2# &
EXPOUT1# & EXPOUT2# &
.
.
.
(EXPIN#) for each DM9081 chip. This function is
easily implemented in a PAL device, using the
following logical equations:
Note that if the design includes only two DM9081
chips, then EXPOUT1# is connected to EXPIN2#,
EXPOUT2# is connected to EXPIN1#, and no
external logic is required. A single PAL16L8 performs
the arbitration function for a repeater based on
several DM9081 chips.
.
.
.
….. EXPOUTn#
….. EXPOUTn#
….. EXPOUTn#
….. EXPOUTN-1#
10BASE-T Hub Controller
.
.
.
Version: DM9081-DS-F02
DM9081
February 02, 2001
Final