Visible to Intel only — GUID: ngo1490746699998
Ixiasoft
Visible to Intel only — GUID: ngo1490746699998
Ixiasoft
5.2.2. Avalon® -ST Pass-Through Interface Signals
Signal | Type | Function | |
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gen_tx_ready | Output | Indicates that the IP core is ready to receive data on the next clock cycle. Asserted by the Avalon® -ST sink to mark ready cycles, which are the cycles in which transfers can take place. If ready is asserted on cycle N, the cycle (N+READY_LATENCY) is a ready cycle. In the RapidIO IP core, READY_LATENCY is equal to 1, so the cycle immediately following the rising clock edge on which gen_tx_ready is detected as asserted is the ready cycle. This signal may alternate between 0 and 1 when the Avalon® -ST pass-through transmitter interface is idle. After gen_tx_valid is asserted, gen_tx_ready remains asserted for the duration of the packet transmission, unless the Physical layer transmit buffer fills. |
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gen_tx_valid 40 | Input | Used to qualify all the other transmit side of the Avalon® -ST pass-through interface input signals. On every ready cycle in which gen_tx_valid is high, data is sampled by the IP core. | |
gen_tx_startofpacket | Input | Marks the active cycle containing the start of the packet40 | |
gen_tx_endofpacket | Input | Marks the active cycle containing the end of the packet.40 | |
gen_tx_data | Input | A 32-bit wide data bus for 1x variations, or a 64-bit wide data bus for 2x or 4x variations. Carries the bulk of the information transferred from the source to the sink.40 | |
gen_tx_empty | Input | This bus identifies the number of empty bytes on the last data transfer of the gen_tx_endofpacket. For a 32-bit wide data bus, this bus is 2 bits wide. For a 64-bit wide data bus, this bus is 3 bits wide. The least significant bit is ignored and assumed to be 0. The following values are supported: | |
32-bit bus: 2'b0X none 2'b1X [15:0] |
64-bit bus: 3'b00X none 3'b01X [15:0] 3'b10X [31:0] 3'b11X [47:0] |
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gen_tx_error | Input | If asserted any time during the packet transfer, this signal indicates the corresponding data has an error and causes the packet to be dropped by the IP core. A value of zero on any beat indicates the data on that beat is error-free.40 |
Signal | Type | Function | |
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gen_rx_ready | Input | Indicates to the IP core that the user’s custom logic is ready to receive data on the next clock cycle. Asserted by the sink to mark ready cycles, which are cycles in which transfers can occur. If ready is asserted on cycle N, the cycle (N+READY_LATENCY) is a ready cycle. The RapidIO IP core is designed for READY_LATENCY equal to1. | |
gen_rx_valid 41 | Output | Used to qualify all the other output signals of the receive side pass-through interface. On every rising edge of the clock where gen_rx_valid is high, gen_rx_data can be sampled. | |
gen_rx_startofpacket | Output | Marks the active cycle containing the start of the packet.41 | |
gen_rx_endofpacket | Output | Marks the active cycle containing the end of the packet.41 | |
gen_rx_data | Output | A 32-bit wide data bus for 1x mode, or a 64-bit wide data bus for 2x or 4x mode.41 | |
gen_rx_empty | Output | This bus identifies the number of empty bytes on the last data transfer of the gen_rx_endofpacket. For a 32-bit wide data bus, this bus is 2 bits wide. For a 64-bit wide data bus, this bus is 3 bits wide. The least significant bit is ignored and assumed to be 0. The following values are supported: | |
32-bit bus: 2'b0X none 2'b1X [15:0] |
64-bit bus: 3'b00X none 3'b01X [15:0] 3'b10X [31:0] 3'b11X [47:0] |
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If the received number of bytes, including padding and CRC, is a multiple of four (for a 32-bit wide data bus) or a multiple of eight (for a 64-bit wide data bus), the value of gen_rx_empty is zero. The value of gen_rx_empty does not tell you whether the final 16 bits of the data transfer are padding or CRC bits; your custom logical layer application must decode the header fields to determine how to interpret the received bits. |
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gen_rx_size 42 | Output | Identifies the number of cycles the current packet transfer requires. This signal is only valid on the start of packet cycle when gen_rx_startofpacket is asserted.41 | |
gen_rx_error | Output | Indicates that the corresponding data has an error. This signal is never asserted by the RapidIO IP core.41 |