Altera UG-01080 Guia do Utilizador Página 170

  • Descarregar
  • Adicionar aos meus manuais
  • Imprimir
  • Página
    / 484
  • Índice
  • MARCADORES
  • Avaliado. / 5. Com base em avaliações de clientes
Vista de página 169
8–18 Chapter 8: PHY IP Core for PCI Express (PIPE)
Link Equalization for Gen3 Data Rate
Altera Transceiver PHY IP Core November 2012 Altera Corporation
User Guide
Phase 0
Phase 0 includes the following steps:
1. Upstream component enters Phase 0 of equalization during Recovery.Rcvrconfig
by sending EQ TS2 training sets with starting presets for the downstream
component. EQ TS2 training sets may be sent at 2.5 GT/s or 5 GT/s.
2. The downstream component enters Phase 0 of equalization after exiting
Recovery.Speed at 8 GT/s. It receives the starting presets from the training
sequences and applies them to its transmitter. At this time, upstream component
has entered Phase 1 and is operating at 8 GT/s.
3. To move to Phase 1, the receiver must have a BER < 10
-4
and should be able to
decode enough consecutive training sequences.
4. The downstream component must detect training sets with Equalization Control
(EC) bits set to 2’b01 in order to move to EQ Phase 1.
Phase 1
During Phase 1 of equalization process, the link partners exchange FS (Full Swing)
and LF (Low Frequency) information. These values represent the upper and lower
bounds for the TX coefficients. The receiver uses this information to calculate and
request the next set of transmitter coefficients.
1. Once training sets with EC bits set to 1’b0 are captured on all lanes, the upstream
component moves to EQ Phase 2 sending EC=2’b10 along with starting pre-cursor,
main cursor, and post-cursor coefficients.
2. The downstream component detects these new training sets, and moves to EQ
Phase 2.
Phase 2 (Optional)
During Phase 2, the Endpoint tunes the TX coefficients of the Root Port. The TS1 Use
Preset bit determines whether the Endpoint uses presets for coarse resolution or
coefficients for fine resolution.
1 If you are using the PHY IP Core for PCI Express (PIPE) PCI Express as an Endpoint,
you cannot perform Phase 2 tuning. The PIPE interface does not provide any
measurement metric to the Root Port to guide coefficient preset decision making. The
Root Port should reflect the existing coefficients and move to the next phase. The
default Full Swing (FS) value advertized by Altera device is 40 and Low Frequency
(LF) is 13.
If you are using the PHY IP Core for PCI Express (PIPE) PCI Express as Root Port, the
End Point can tune the Root Port TX coefficients.
Vista de página 169
1 2 ... 165 166 167 168 169 170 171 172 173 174 175 ... 483 484

Comentários a estes Manuais

Sem comentários