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Ethernet Media Access Controller (EMAC) Registers

5.37 MAC Hash Address Register 1 (MACHASH1)

The MAC hash registers allow group addressed frames to be accepted on the basis of a hash function of the address. The hash function creates a 6-bit data value (Hash_fun) from the 48-bit destination address (DA) as follows:

Hash_fun(0)=DA(0) XOR DA(6) XOR DA(12) XOR DA(18) XOR DA(24) XOR DA(30) XOR DA(36) XOR DA(42); Hash_fun(1)=DA(1) XOR DA(7) XOR DA(13) XOR DA(19) XOR DA(25) XOR DA(31) XOR DA(37) XOR DA(43); Hash_fun(2)=DA(2) XOR DA(8) XOR DA(14) XOR DA(20) XOR DA(26) XOR DA(32) XOR DA(38) XOR DA(44); Hash_fun(3)=DA(3) XOR DA(9) XOR DA(15) XOR DA(21) XOR DA(27) XOR DA(33) XOR DA(39) XOR DA(45); Hash_fun(4)=DA(4) XOR DA(10) XOR DA(16) XOR DA(22) XOR DA(28) XOR DA(34) XOR DA(40) XOR DA(46); Hash_fun(5)=DA(5) XOR DA(11) XOR DA(17) XOR DA(23) XOR DA(29) XOR DA(35) XOR DA(41) XOR DA(47);

This function is used as an offset into a 64-bit hash table stored in MACHASH1 and MACHASH2 that indicates whether a particular address should be accepted or not.

The MAC hash address register 1 (MACHASH1) is shown in Figure 77 and described in Table 76.

 

Figure 77. MAC Hash Address Register 1 (MACHASH1)

31

16

 

MACHASH1

 

R/W-0

15

0

MACHASH1

R/W-0

LEGEND: R = Read only; R/W = Read/Write; -n= value after reset

Table 76. MAC Hash Address Register 1 (MACHASH1) Field Descriptions

Bit

Field

Value

Description

31-0

MACHASH1

0-FFFF FFFFh

Least-significant 32 bits of the hash table corresponding to hash values 0 to 31. If a hash

 

 

 

table bit is set, then a group address that hashes to that bit index is accepted.

5.38 MAC Hash Address Register 2 (MACHASH2)

The MAC hash address register 2 (MACHASH2) is shown in Figure 78 and described in Table 77.

 

Figure 78. MAC Hash Address Register 2 (MACHASH2)

31

16

 

MACHASH2

 

R/W-0

15

0

MACHASH2

R/W-0

LEGEND: R = Read only; R/W = Read/Write; -n= value after reset

Table 77. MAC Hash Address Register 2 (MACHASH2) Field Descriptions

Bit

Field

Value

Description

31-0

MACHASH2

0-FFFF FFFFh

Most-significant 32 bits of the hash table corresponding to hash values 32 to 63. If a hash

 

 

 

table bit is set, then a group address that hashes to that bit index is accepted.

SPRUEQ6–December 2007

Ethernet Media Access Controller (EMAC)/Management Data Input/Output (MDIO)

117

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Texas Instruments TMS320DM646x manual MAC Hash Address Register 1 MACHASH1, MAC Hash Address Register 2 MACHASH2
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TMS320DM646x specifications

The Texas Instruments TMS320DM646x series is a powerful family of digital media processors designed to handle high-performance applications in video, imaging, and audio processing. These devices leverage advanced technologies to deliver efficient processing capabilities for a variety of embedded systems, making them ideal for multimedia solutions.

At the core of the TMS320DM646x is the versatile DSP architecture, which optimizes performance for digital signal processing tasks. This architecture allows for real-time processing, enabling the devices to handle complex algorithms necessary for image and video compression, thereby meeting the rigorous demands of modern multimedia applications.

One of the standout features of the TMS320DM646x series is its dual-core architecture. This consists of a Digital Signal Processor (DSP) alongside an ARM-based application processor. The DSP is predominantly employed for critical processing tasks, allowing it to execute high-throughput data streams efficiently, while the ARM processor manages control tasks and user interfaces. This division of labor enhances overall system performance and responsiveness.

The series supports a wide range of video formats and technologies, including HD video encoding and decoding, which accommodates HD resolution content essential for today’s multimedia applications. Furthermore, the TMS320DM646x integrates hardware accelerators for video compression standards such as H.264 and MPEG-4, which significantly reduce the processing burden on the CPU, resulting in lower power consumption and higher efficiency.

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Overall, the Texas Instruments TMS320DM646x series offers an exceptional combination of processing power, advanced multimedia capabilities, and energy efficiency. It optimally supports a wide array of applications, from video processing and image analysis to audio encoding. This comprehensive feature set, along with its robust architecture, positions the TMS320DM646x as a leading choice for developers in the digital media space.
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