wiki:Software/Firmware/Framework/R3_arch/outline/blk_spec/pkt/tx/cmd_gen

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


..

Last modified 7 years ago Last modified on 06/18/10 14:28:20

Attachments (1)

Download all attachments as: .zip