The device has two PCI Express physical ports - PCIe 0 and PCIe 1. Each of the two device PCIe ports has an associated PMA (physical media attachment) component pair of a high-speed operating differential transmitter (serializer) and a differential receiver (de-serializer). While the device PCIe port 0 PHY is always mapped to device PCIe_SS1 controller, the device PCIe port 1 PHY can be software multiplexed to the PCIe_SS1 (dual-lane configuration) or to the PCIe_SS2 (single-lane configuration) . In addition, the PCIe shared PHY subsystem encompasses a PCIe PCS (physical coding sublayer), a PCIe power management logic, APLL, a DPLL reference clock generator and an APLL low-jitter clock buffer.
- PCIe PCS (a physical coding sublayer component) converts an 8-bit portion of parallel data over a PCIe lane to a 10-bit parallel data to adapt the process of serialization and deserialization in the TX/RX PHYs to various requirements. At the same time it transforms the transmission rate to maintain the PCIe Gen2 bandwidth.
- A programmable multiplexing logic which maps either PCIe_SS1 or PCIe_SS2 PCS logic to PCIe port 1 PHY.
- PHY serializer (TX) and deserializer (RX) components with associated power control logic, building the so called PMA (physical media attachment) part.
- DPLL_PCIe_REF is a DPLL clock source, controlled from the device PRCM, that provides (typically 20 MHz/100 MHz) clock to the PCIe PHY serializer/de-serializer components reference clock inputs.
- Contains an integrated APLL (APLLPCIe) which multiplies the DPLL_PCIe_REF clock to 2.5 GHz.
- The APLLPCIe low-jitter buffer and additional logic takes care to provide the PCIe APLL reference input clock.
- An L4_CFG interface adapter - OCP2SCP3 enables accessing the PCIe PHY serial configuration protocol compatible (SCP) registers via L4_CFG interconnect accesses.
Figure 28-15 shows an overview of the device PCIe subsystem with its integrated components.