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
14 years ago
Last modified on Jun 18, 2010, 6:28:20 PM
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