MDS105 Datasheet, PDF (26/35 Pages) Zarlink Semiconductor Inc – Unmanaged 5-Port 10/100 Mbps Ethernet Switch

MDS105
Data Sheet
12.1 Strap Options
The Strap options are relevant during the initial power-on period, when reset is asserted. During reset, the MDS105
will examine the boot strap address pin to determine its value and modify the internal configuration of the chip
accordingly.
“1” means Pull-up
“0” means Pull-down with an external 1 K Ohm
Default value is 1, (all boot strap pins have internal pull-up resistor).
Pin No(s).
Symbol
Name & Functions
Boot Strap Pins
206 (L_A[5])
Memory Size
1 - Memory size = 256 KB
0 - Memory size = 512 KB
208 (L_A [6])
EEPROM
1 - NO EEPROM Installed
0 - EEPROM Installed¹
151 (L_A[17])
Port 4 MII/Serial 1 - MII Mode for port 4
0 - Serial mode for port 4
150 (L_A[2])
Link Polarity
Link Polarity for serial interface
1 - Active Low
0 - Active High
204 (L_A[3])
FDX Polarity
Full/Half Duplex Polarity for serial interface
1 - Active Low
0 - Active High
205 (L_A[4])
133 (TST[2])
SPD100 Polarity
SBRAM Self Test
Speed polarity for serial interface
1 - Active Low
0 - Active High
For Board/System Manufacturing Test²
1 - Disable
0 - Enable
1. If the MDS105 is configured from EEPROM preset (L_A[6] pulled down at reset), it will try to load its configuration from the EEPROM. If the
EEPROM is blank or not preset, it will not boot up. The parallel port can be used to program the EEPROM at any time.
2. During normal power-up, the MDS105 will run through an external SBRAM memory test to ensure that there are no memory interface prob-
lems. If a problem is detected, the chip will stop functioning. To facilitate board debug in the event that a system stops functioning, the
MSD105 can be put into a continuous SBRAM self test mode to allow an operator to determine if there are stuck pins in the memory interface
(using network analyzer).
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Zarlink Semiconductor Inc.