4.3. Avalon® Streaming Interface Signals
| Signal | Direction | Width | Description | 
|---|---|---|---|
| avalon_st_tx_startofpacket[] | In | [NUM_CHANNELS] | Assert this signal to indicate the beginning of the TX data. | 
| avalon_st_tx_endofpacket[] | In | [NUM_CHANNELS] | Assert this signal to indicate the end of the TX data. | 
| avalon_st_tx_valid[] | In | [NUM_CHANNELS] | Assert this signal to indicate that the avalon_st_tx_data signal and other signals on this interface are valid. | 
| avalon_st_tx_ready[] | Out | [NUM_CHANNELS] | When asserted, indicates that the MAC IP is ready to accept data. The reset value of this signal is nondeterministic. | 
| avalon_st_tx_error[] | In | [NUM_CHANNELS] | Assert this signal to indicate that the current TX packet contains errors. | 
| avalon_st_tx_data[][] | In | [NUM_CHANNELS][m] | TX data from the client. m is 64 when the Use legacy Avalon Streaming Interface parameter is selected. Otherwise, m is 32. | 
| avalon_st_tx_empty[][] | In | [NUM_CHANNELS][m] | Use this signal to specify the number of empty bytes in the cycle that contain the end of the TX data. m is 3 when the Use legacy Avalon Streaming Interface parameter is selected. Otherwise, m is 2. 
 | 
| avalon_st_rx_startofpacket[] | Out | [NUM_CHANNELS] | When asserted, indicates the beginning of the RX data. | 
| avalon_st_rx_endofpacket[] | Out | [NUM_CHANNELS] | When asserted, indicates the end of the RX data. | 
| avalon_st_rx_valid[] | Out | [NUM_CHANNELS] | When asserted, indicates that the avalon_st_rx_data signal and other signals on this interface are valid. | 
| avalon_st_rx_ready[] | In | [NUM_CHANNELS] | Assert this signal when the client is ready to accept data. | 
| avalon_st_rx_error[][] | Out | [NUM_CHANNELS][6] | When set to 1, the respective bits indicate an error type: 
 | 
| avalon_st_rx_data[][] | Out | [NUM_CHANNELS][m] | RX data to the client. m is 64 when the Use legacy Avalon Streaming Interface parameter is selected. Otherwise, m is 32. | 
| avalon_st_rx_empty[][] | Out | [NUM_CHANNELS][m] | Contains the number of empty bytes during the cycle that contain the end of the RX data. m is 3 when the Use legacy Avalon Streaming Interface parameter is selected. Otherwise, m is 2. | 
| avalon_st_txstatus_valid[] | Out | [NUM_CHANNELS] | When asserted, this signal qualifies the avalon_st_txstatus_data and avalon_st_txstatus_error signals. | 
| avalon_st_txstatus_data[][] | Out | [NUM_CHANNELS][40] | Contains information about the TX frame. 
 | 
| avalon_st_txstatus_error[][] | Out | [NUM_CHANNELS][7] | When set to 1, the respective bit indicates the following error type in the TX frame: 
 The error status is invalid when an overflow occurs. | 
| avalon_st_rxstatus_valid[] | Out | [NUM_CHANNELS] | When asserted, this signal qualifies the avalon_st_rxstatus_data and avalon_ st_rxstatus_error signals. The MAC IP asserts this signal in the same clock cycle the avalon_st_rx_ endofpacket signal is asserted. | 
| avalon_st_rxstatus_data[][] | Out | [NUM_CHANNELS][40] | Contains information about the RX frame. 
 | 
| avalon_st_rxstatus_error[][] | Out | [NUM_CHANNELS][7] | When set to 1, the respective bit indicates the following error type in the RX frame. 
 The error status is invalid when an overflow occurs. | 
| avalon_st_pause_data[][] | In | [NUM_CHANNELS][2] | This signal takes effect when the register bits, tx_pauseframe_enable[2:1], are both set to the default value 0. Set this signal to the following values to trigger the corresponding actions. 
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