Altera IP Compiler for PCI Express - Manual (Page 334)

B–16 Chapter :
Descriptor/Data Interface
IP Compiler for PCI Express User Guide August 2014 Altera Corporation
Table B–10 shows the bit information for tx_cred [65:0] for the ×8 IP cores.
[11]
■ 0: No credits available
■ 1: Sufficient credit available for at
least 1 transaction layer packet Non-Posted data.
[12]
■ 0: No credits available
■ 1: Sufficient credit available for at
least 1 transaction layer packet Completion header.
[21:13]
9 bits permit advertisement of 256
credits, which corresponds to 4 KBytes,
the maximum payload size.
Completion data, posted data.
Table B–9. tx_cred0[21:0] Bits for the ×1 and ×4 IP cores (Part 2 of 2)
Bits Value Description
Table B–10. tx_cred[65:0] Bits for ×8 IP core
Bits Value Description
tx_cred[7:0]
■ 0-127: Number of credits available
■ >127: No credits available
Posted header. Ignore this field if the value of
posted header credits, tx_cred[60], is set to
1.
tx_cred[19:8]
■ 0-2047: Number of credits available
■ >2047: No credits available
Posted data. Ignore this field if the value of
posted data credits, tx_cred[61], is set to 1.
tx_cred[27:20]
■ 0-127: Number of credits available
■ >127: No credits available
Non-posted header. Ignore this field if value of
non-posted header credits, tx_cred[62], is
set to 1.
tx_cred[39:28]
■ 0-2047: Number of credits available
■ >2047: No credits available
Non-posted data. Ignore this field if value of
non-posted data credits, tx_cred[63], is set
to 1.
tx_cred[47:40]
■ 0–127: Number of credits available
■ >127: No credits available
Completion header. Ignore this field if value of
CPL header credits, tx_cred[64], is set to 1.
tx_cred[59:48]
■ 0-2047: Number of credits available
■ >2047: No credits available
Completion data. Ignore this field if value of
CPL data credits, tx_cred[65], is set to 1.
tx_cred[60]
■ 0: Posted header credits are not infinite
■ 1: Posted header credits are infinite
Posted header credits are infinite when set to
1.
tx_cred[61]
■ 0: Posted data credits are not infinite
■ 1: Posted data credits are infinite
Posted data credits are infinite.when set to 1.
tx_cred[62]
■ 0: Non-Posted header credits are not infinite
■ 1: Non-Posted header credits are infinite
Non-posted header credits are infinite when set
to 1.
tx_cred[63]
■ 0: Non-posted data credits are not infinite
■ 1: Non-posted data credits are infinite
Non-posted data credits are infinite when set to
1.
tx_cred[64]
■ 0: Completion credits are not infinite
■ 1: Completion credits are infinite
Completion header credits are infinite when set
to 1.
tx_cred[65]
■ 0: Completion data credits are not infinite
■ 1: Completion data credits are infinite
Completion data credits are infinite when set to
1.