Command Generator

Figure 1 - Command Generator IO

Table 1 - Rx Ethernet Interface

Signal Name	In/Out	Width	Description
sof	In	1	Start-of-frame signal, indicating first word of payload
eof	In	1	End-of-frame signal, indicating last word of payload
data	In	32	Ethernet payload data
rd_en	Out	1	Active High. Fifo data fetch enable signal
fifo_empty_flag	In	1	Fifo empty flag

Table 2 - RMAP Interface

Signal Name	In/Out	Width	Description
buf_full_err	Out	1	Active High. Indicates that the buffer is full and no more data can be accepted.
frame_seq_no	Out	1	Sequence no of the data frame which was not stored in the buffer due to a buf_full_err,
			or cmd_full_err, or a frame_length_err.
cmd_full_err	Out	1	Active High. Indicates that the command fifo is full and no more commands can be accepted.
hdr_err	Out	1	Active High. Indicates that there is an error in the IP header not enough no. of words
ip_addr_err	Out	1	Active High. Indicates that the destination IP address in the data frame does not match
			with the IP address of the board.
frame_length_err	Out	1	Active High. Indicates that the frame length calculated from IP payload length does not
			match with the actual frame length.
			In case of a control command, it might indicate that the frame length is not equal to 2 words (8 bytes).
			In case of a data command, if the actual frame length is more than the calculated length, only the
			calculated length no.of words are stored and the rest are discarded. If the actual frame length is
			less, the write operation is considered incomplete and is canceled.

Table 3 - Command FIFO Interface

Signal Name	In/Out	Width	Description
cmd_sof	Out	1	Start-of-frame signal, indicating the first word of command descriptor
cmd_eof	Out	1	End-of-frame signal, indicating the last(second) word of command descriptor
cmd_data	Out	32	Command descriptor word
cmd_write	Out	1	Active High. Indicates that the current word on cmd_data is valid and acts a write request for the command FIFO.
cmd_full_flag	In	1	Active High. Indicates that the command FIFO is full and can not accept any commands

Table 4 - Memory Control Interface

Signal Name	In/Out	Width	Description
buf_wr_req	Out	1	Active high. Signal requesting the memory control for buf_wr_size bytes of space on the buffer to store data
buf_wr_size	Out	16	Size of data to be stored in the buffer(bytes) . It is calculated from the payload length given in the IP header
buf_wr_ack	In	1	Active High. Response to buf_wr_req indicating that the requested space is available at the address buf_wr_ptr.
			buf_wr_ack is sent as soon as buf_wr_req is detected by the memory control, i.e., the command descriptor generator
			can send a buffer request and check for buf_wr_ack in the next clock cycle. If buf_wr_ack is not high, it means that
			the requested buffer space is not available.
buf_wr_ptr	In	16	Address at which the data would be written. This address will be inserted in the data command descriptor.
buf_sof	Out	1	Start-of-frame for the app data to be stored. The memory control expects an sof (or a buf_wr_cancel) as soon as the
			buf_wr_req is pulled low. If the buf_wr_req remains low for a clock cycle or more before sending the sof, then the
			data write operation is ignored.
buf_eof	Out	1	End-of-frame for the app data to be stored
buf_wr_data	Out	32	App data word to be stored
buf_data_valid	Out	1	Active High. Indicates that the data word on buf_wr_data is valid
buf_wr_cancel	Out	1	Active High. Command descriptor generator can cancel a data write operation at any time, by setting this signal high.
			A write operation starts when the buffer request is sent to the memory control and ends when eof is sent.

Table 5 - RMAP Processor Interface

Signal Name	In/Out	Width	Description
rmap_sof	Out	1	Start-of-frame signal, indicating first word of RMAP descriptor/message
rmap_eof	Out	1	End-of-frame signal, indicating last word of RMAP descriptor/message
rmap_data	Out	32	RMAP descriptor data
rmap_wr_en	Out	1	Active High. Fifo write enable signal
rmap_fifo_full_flag	In	1	Fifo full flag

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