SNLA479 April   2025 DP83822HF , DP83822IF , DP83869HM

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1What is Fiber?
    1. 1.1 Pins Used
    2. 1.2 Hardware Configurations
    3. 1.3 Useful Registers
  5. 2Common Use Cases
  6. 3Summary
  7. 4References

Pins Used

For each device, there are fives pins used for fiber communication. However, as best practice, make sure that the PHY is bootstrapped into the respective modes for fiber operation.

Table 1-1 DP83822 Fiber Pins
Pin Name (Number) Functionality
TD_P (12) Transmitting Pins. Output of the PHY.
TD_M (11)
RD_P (10) Receiving Pins. Input of the PHY.
RD_M (9)
LED_1/GPIO1 (24) Signal Detect. Typically connected to SFP module which helps determine if communication has been interrupted and relays to PHY to drop link. Use other LED pins for appropriate functionalities
Table 1-2 DP83822 Fiber Bootstrapping
Pin Name (Number) Strap Mode Description
COL (29) 2 or 3 Enables FX_EN
LED_0 (17) 1 Half Duplex
4 (Default) Full Duplex
RX_ER (28) 3 or 4 (Default) Signal Detect Enable
Table 1-3 DP83869 Fiber Pins
Pin Name (Number) Functionality
SOP (15) Transmitting Pins. Output of the PHY.
SON (14)
SIP (16) Receiving Pins. Input of the PHY.
SIN (17)
JTAG_TDI/SD (24) Signal Detect. Typically connected to SFP module which helps determine if communication has been interrupted and relays to PHY to drop link.
Table 1-4 DP83869 Fiber Bootstrapping
Pin Name (Number) Strap Name OPMODE[2] OPMODE[1] OPMODE[0] Functional Mode
RX_D2 (35) OPMODE[2] 0 0 1 RGMII to 1000BASE-X
RX_D3 (36) OPMODE[1] 0 1 0 RGMII to 100BASE-FX
JTAG_TDO/GPIO_1 (22) OPMODE[0] 1 0 0 Media Convertor (1000BASE-T to 1000BASE-X): 1000Mbps
1 0 1 Media Convertor (100BASE-Tx to 100BASE-Fx): 100Mbps