CX11656 HomePlug 1.0 PHY Data Sheet
3.2
GPSI Interface with SPI Control
The General Purpose Serial Interface (GPSI) is a flexible, bi-directional serial interface
that can be utilized in place of the MII. It provides a straightforward interface to a
communications controller through a synchronous serial data stream for transmit and
receive data. When using the GPSI interface, the management interface can either be
MDI or SPI, selected by the MDI_SPIS_N pin. The information that follows describes
the GPSI communication interface along with the SPI management interface as a typical
example.
The GPSI interface signals are shown in Figure 3-14.
Figure 3-14. GPSI Data Interface with SPI Control
CX11656
GPSI_RXD
GPSI_RXCLK
GPSI_RXEN
GPSI_COL
GPSI_TXBSY
GPSI_TXD
External
Interface
Block
PowerPacket
MAC
PowerPacket
PHY
GPSI_TXCLK
Host
Controller
GPSI_TXEN
SPIS_SDO
SPIS_SDI
SPIS_SCLK
SPIS_CS_N
102069_018
3.2.1
GSPI Interface
GPSI is an interoperable interface providing a simple interconnection between the
CX11656 and embedded microcontrollers. Data is transferred between the host controller
and the CX11656 over separate 1-bit transmit and receive data paths synchronous with
clock signals supplied to the host by the CX11656.
3.2.1.1
GPSI Timing Diagrams
The figures below show the transmission and reception of packets and the corresponding
behavior of the GPSI interface. A packet is transferred from the host when GPSI_TXEN
goes high. An unsuccessful attempt is made to transmit a packet in Case 5. The received
packet is passed to the host when GPSI_RXEN is high.
The GSPI flow control is illustrated in Figure 3-15.
The GSPI transmit and receive timing are illustrated in Figure 3-16 and Figure 3-17,
respectively.
3-12
Conexant Proprietary and Confidential Information
102069A
CONEXANT [ CONEXANT SYSTEMS, INC ]
