BL702/704/706 Reference Manual
17.7.2 Send data frame
• Configure bit fields such as data frame format and interval in the EMAC_MODE register
• By configuring the TXBDNUM field in the EMAC_TX_BD_NUM register to specify the number of BDs used for
transmission, the remaining BDs are RX BDs
• Prepare the data frame to be sent in the memory
• Fill in the address of the data frame into the data pointer field (word 1) corresponding to the sent BD
• Clear the status flag in the control and status field (wrod 0) corresponding to the sent BD, and set the control field
(CRC enable, PAD enable, interrupt enable, etc.)
• Write the length of the data frame and set the RD field to inform EMAC that this BD data needs to be sent; if
necessary, set the IRQ bit to enable interrupts
• In particular, if it is the last BD sent, the WR bit needs to be set, and EMAC will ”wrap around” to the first sent BD
for processing after processing this BD
• If there are multiple BDs to be sent, repeat the steps of setting BD to fill all sending BDs
• If you need to enable the transmit interrupt, you also need to configure the TX related bits in the EMAC_INT_MASK
register
• Configure the TXEN bit in the EMAC_MODE register to enable transmission
• If the interrupt is enabled, in the interrupt sent, the current BD can be obtained through the TXBDNUM field in the
EMAC_TX_BD_NUM register
• Perform corresponding processing according to the current BD status word
• For the BD whose data has been sent, the RD bit in the control field will be cleared by hardware and will not be
sent again; after filling in new data, set RD, and this BD can be used for sending again
17.7.3 Receive data frame
• Configure bit fields such as data frame format and interval in the EMAC_MODE register
• By configuring the TXBDNUM field in the EMAC_TX_BD_NUM register to specify the number of BDs used for
transmission, the remaining BDs are RX BDs
• The area in the memory that is ready to receive data
• Fill in the address of the data frame into the data pointer field (word 1) corresponding to the received BD
• Clear the status flag in the control and status field (wrod 0) corresponding to the sending BD, and set the control
field (interrupt enable, etc.)
• Write the receivable data frame length and set the E bit field to inform EMAC that the BD is idle and can be used
for data reception; if necessary, set the IRQ bit to enable interrupts
BL702/704/706 Reference Manual 294/ 375
@2021 Bouffalo Lab
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