Digi NS9750 Uživatelský manuál stáhnout pdf (Strana 63)

Ethernet timing

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Ethernet timing

Ethernet AC characteristics are measured with 10pF, unless otherwise noted.

Table 29 describes the values shown in the Ethernet timing diagrams.

Notes:

1 Minimum specification is for fastest AHB bus clock of 100 MHz. Maximum specification is for slowest

AHB bus clock of 50 MHz.

2 C

load

= 10pF for all outputs and bidirects.

3 No setup and hold requirements for cam_reject because it is an asynchronous input. This is also true for RMII

PHY applications.

Parameter Description Min Max Unit Notes

E1 MII tx_clk to txd, tx_en, tx_er 3 11 ns 2

E2 MII rxd, rx_dv, rx_er setup to rx_clk rising 3 ns

E3 MII rxd, rx_dv, rx_er hold from rx_clk rising 1 ns

E4 mdio (input) setup to mdc rising 10 ns

E5 mdio (input) hold from mdc rising 0 ns

E6 mdc to mdio (output) 18 38 ns 1, 2

E7 mdc period 80 ns

E8 RMII ref_clk to txd, tx_en 3 12 ns 2

E9 RMII rxd, crs, rx_er setup to ref_clk rising 3 ns

E10 RMII rxd, crs, rx_er hold from ref_clk rising 1 ns

E11 MII rx_clk to cam_req 3 10 ns

E12 MII cam_reject setup to rx_clk rising N/A ns 3

E13 MII cam_reject hold from rx_clk rising N/A ns 3

Table 29: Ethernet timing characteristics

1 2 ... 58 59 60 61 62 63 64 65 66 67 68 ... 87 88

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Digi NS9750 Uživatelský manuál Strana 63