DSP对网卡的通信过程控制就是DSP对DP8390中各种寄存器进行编程

The communication process control of the DSP to the network card is that the DSP performs programming control on various registers in the DP8390 to complete the correct transmission and reception of data packets. All internal registers of DP8390 are 8-bit and mapped to 4 pages. Each page has 16 register addresses (RA=00OH ~ 0fH) that can be read and written. The selection of the page is controlled by the command register CA. The register on page 0 is used for the receiving and sending process, the register on page 1 is mainly used for DP8390 initialization, and the register on page 2 is used for loop diagnosis. The operation of the DSP on the register is to use the register as a port device of the DSP, and its actual physical port address (PPA) is the sum of the basic I/0 port address (BI0A) of the network card and the register address (RA) (ie PPA=BI0A+RA). It should be noted that there is no one-to-correspondence between PPA and register. The read operation and write operation of PPA are not the same-it must be done on the same register. This situation is especially obvious on page 0 . The user data packet interaction between the DSP and the network card is realized through the data port of the network card, and the data packet can be read in or sent to the RAM buffer of the network card either by DMA mode or PIO mode. In this system, DSP uses DMA to read and write data to the network card. The data port address (NDPA) of the network card is the basic I/0 address (BI0A) of the network card plus the offset address 10H (that is, NDPA=BI0A+10H).

The communication process control of DSP to the network card is that DSP programs and controls various registers in dp8390 to complete the correct sending and receiving of data packets. All internal registers of the dp8390 are 8 bits, mapped to 4 pages. Each page has 16 register addresses for reading and writing (RA = 00oh ~0fh). The selection of the page is controlled by the command register ca. The register on page 0 is used for transceiver process, the register on page 1 is mainly used for dp8390 initialization, and the register on page 2 is used for loop diagnosis. DSP operates the register as the port device of DSP, and its actual physical port address (PPA) is the sum of the basic I / 0 port address (bi0a) of the network card and the register address (RA) (i.e. PPA = bi0a + RA). It should be noted that there is no one register correspondence between PPA and registers, and the read and write operations of PPA are not necessarily performed on the same register, which is particularly obvious on page 0. The interaction of user data packets between DSP and network card is realized through the data port of network card. Data packets can be read in by DMA or PIO or sent to the RAM buffer of network card. In this system, DSP uses DMA to read and write data to the network card. The data port address (ndpa) of the network card is the basic I / 0 address (bi0a) of the network card plus the offset address 10h (i.e. ndpa = bi0a + 10h).<br>

The communication process control of DSP for network card is that DSP programs and controls various registers in DP8390 to complete the correct sending and receiving of data packets. All internal registers of DP8390 are 8 bits, which are mapped to 4 pages. Each page has 16 register addresses for reading and writing (RA=00OH ~0fH). Page selection is controlled by command register CA. Page 0 register is used for transceiving process, page 1 register is mainly used for initialization of DP8390, and page 2 register is used for loop diagnosis. The register is operated by DSP as the port device of DSP, and its actual physical port address (PPA) is the sum of the basic I/O port address (BI0A) of the network card and the register address (RA) (i.e. PPA=BI0A+RA). It should be noted that there is no one-to-one correspondence between PPA and registers, and the read operation and write operation on PPA are not the same-to-register, which is especially obvious on page 0. The interaction of data packets between DSP and NIC is realized through the data port of NIC, which can be read in by DMA or PIO or sent to RAM buffer of NIC. In this system, DSP uses DMA to read and write data to the network card. The data port address (NDPA) of the network card is the basic I/O address (BI0A) of the network card plus an offset address of 10H (that is, NDPA=BI0A+10H).