Datasheet
2017 Microchip Technology Inc. DS00002245B-page 11
KSZ8041NL/RNL
2.2 STRAP-IN OPTION – KSZ8041NL
Pin strap-ins are latched during power-up or reset. In some systems, the MAC receive input pins may drive high during
power-up or reset, and consequently cause the PHY strap-in pins on the MII/RMII signals to be latched high. In this
case, it is recommended to add 1K pull-downs on these PHY strap-in pins to ensure the PHY does not strap in to ISO-
LATE mode, or is not configured with an incorrect PHY Address.
Note 2-1 Ipu/O = Input with internal pull-up (40K ±30%) during power-up/reset; output pin otherwise.
Ipd/O = Input with internal pull-down (40K ±30%) during power-up/reset; output pin otherwise.
TABLE 2-2: STRAP-IN OPTION – KSZ8041NL
Pin
Number
Pin Name
Type
(Note 2-1)
Pin Function
15 PHYAD2 Ipd/O The PHY Address is latched at power-up or reset and is configurable to any
value from 1 to 7.
The default PHY Address is 00001.
PHY Address bits [4:3] are always set to ‘00’.
14 PHYAD1 Ipd/O
13 PHYAD0 Ipu/O
18 CONFIG2 Ipd/O The CONFIG[2:0] strap-in pins are latched at power-up or reset and are
defined as follows:
29 CONFIG1 Ipd/O
28 CONFIG0 Ipd/O
20 ISO Ipd/O
ISOLATE mode:
Pull-up = Enable
Pull-down (default) = Disable
During power-up or reset, this pin value is latched into register 0h bit 10.
31 SPEED Ipu/O
SPEED mode:
Pull-up (default) = 100 Mbps
Pull-down = 10 Mbps
During power-up or reset, this pin value is latched into register 0h bit 13 as
the Speed Select, and also is latched into register 4h (Auto-Negotiation
Advertisement) as the Speed capability support.
16 DUPLEX Ipu/O
DUPLEX mode:
Pull-up (default) = Half Duplex
Pull-down = Full Duplex
During power-up or reset, this pin value is latched into register 0h bit 8 as
the Duplex mode.
30 NWAYEN Ipu/O
Nway Auto-Negotiation Enable:
Pull-up (default) = Enable Auto-Negotiation
Pull-down = Disable Auto-Negotiation
During power-up or reset, this pin value is latched into register 0h bit 12.
CONFIG[2:0] Mode
000 MII (default)
001 RMII
010 Reserved - not used
011 Reserved - not used
100 MII 100 Mbps Preamble Restore
101 Reserved - not used
110 Reserved - not used
111 Reserved - not used