Altera POS-PHY Level 2 and 3 Compiler Manuel d'utilisateur télécharger pdf (Page 56)

3–28 Chapter 3: Functional Description

Interface Signals

POS-PHY Level 2 and 3 Compiler User Guide © November 2009 Altera Corporation

Preliminary

Table 3–14 shows the Atlantic control interface signal definitions.

err Error indicator. err indicates that the current packet is aborted and should be discarded. err may be

asserted at any time during the current packet, but once asserted it can only be deasserted on the clock

cycle after eop is asserted. The POS-PHY MegaCore function sees this signal as either terr or rerr,

depending on the data flow direction. Conditions that can cause rerr to be set can be, but are not

limited to, FIFO buffer overflow, abort-sequence detection, missing SOP, missing EOP, and parity errors.

mty[2:0]

mty[1:0]

mty[0:0]

Word empty bytes. mty indicates the number of invalid (empty) bytes of data in dat. The mty bus

should always be all zero, except during the last transfer of a packet on dat. When eop is asserted, the

number of invalid packet data bytes on dat is specified by mty. The definition of mty is compatible

with the mod signal in the POS-PHY level 2 and 3 specifications.

mty = ‘000’, All dat bytes are valid

mty = ‘001’, dat[7:0] are invalid

mty = ‘010’, dat[15:0] are invalid

mty = ‘011’, dat[23:0] are invalid

mty = ‘100’, dat[31:0] are invalid

mty = ‘101’, dat[39:0] are invalid

mty = ‘110’, dat[47:0] are invalid

mty = ‘111’, dat[55:0] are invalid

An 8-bit dat bus requires no mty signal

A 16-bit dat bus requires a mty[0] signal

A 32-bit dat bus requires a mty[1:0] signal

A 64-bit dat bus requires a mty[2:0] signal

mty can only be non-zero when eop is asserted.

Table 3–13. Atlantic Interface Data Signals (Part 2 of 2)

Signal Description

1 2 ... 51 52 53 54 55 56 57 58 59 60 61 62

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Altera POS-PHY Level 2 and 3 Compiler Manuel d'utilisateur Page 56