BT.656 Video Capture Mode

3.2.2BT.656 Timing Reference Codes

For standard digital video, there are two reference signals, one at the begin- ning of each video data block (start of active video, SAV), and one at the end of each video block (end of active video, EAV). (Technically each line begins with the SAV code and ends just before the subsequent EAV code.) Each timing reference signal consists of a four sample sequence in the following for- mat: FF.Ch 00.0h 00.0h XY.0h. (The FFh and 00h values are reserved for use in these timing reference signals.) The first three bytes are a fixed preamble. The fourth byte contains information defining field identification, the state of field blanking and state of line blanking. The assignment of these bits within the timing reference signal is listed in Table 3–2. Note that the two least-signifi- cant bits should be ignored even during 10-bit operation.

Table 3–2. BT.656 Video Timing Reference Codes

Data Bit

1st Byte

2nd Byte

3rd Byte

4th Byte

(FFh)

(00h)

(00h)

(XYh)

 

 

 

 

 

9 (MSB)

1

0

0

1

8

1

0

0

F (field)†

7

1

0

0

V (vertical blanking)‡

6

1

0

0

H (horizontal blanking)§

5

1

0

0

P3 (protection bit 3)

4

1

0

0

P2 (protection bit 2)

3

1

0

0

P1 (protection bit 1)

2

1

0

0

P0 (protection bit 0)

1

x

x

x

x

0

x

x

x

x

† F = 0 during Field 1; F = 1 during Field 2

‡V = 0 elsewhere; V = 1 during field blanking § H = 0 in SAV; H = 1 in EAV

P0, P1, P2, and P3: Depends on F, V, and H state.

3-4

Video Capture Port

SPRU629

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Texas Instruments TMS320C64x DSP manual 2 BT.656 Timing Reference Codes, BT.656 Video Timing Reference Codes
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TMS320C64x DSP specifications

The TMS320C64x DSP family from Texas Instruments represents a significant milestone in the realm of digital signal processing. Launched as part of the C6000 series, the C64x DSPs are designed for high-performance applications requiring intensive computational capabilities, such as telecommunications, audio processing, video processing, and industrial control systems.

One of the standout features of the TMS320C64x DSP is its VLIW (Very Long Instruction Word) architecture, which allows for an exceptionally high level of parallelism. This architecture enables multiple instructions to be executed simultaneously, boosting the overall throughput and allowing for complex data processing tasks to be completed more quickly than with conventional DSPs.

The C64x DSPs also boast an impressive clock frequency range, typically up to 1 GHz, delivering substantial computational power for real-time processing goals. Additionally, these processors feature extensive on-chip memory, including L1 and L2 cache, which significantly enhances data access speeds and helps reduce bottlenecks during high-demand processing tasks.

Another key characteristic of the TMS320C64x family is its support for advanced instruction sets optimized for specific applications. These include SIMD (Single Instruction, Multiple Data) capabilities, allowing for efficient handling of large datasets often involved in multimedia processing or complex signal manipulation.

For connectivity, these DSPs often integrate advanced interfaces such as EMIF (External Memory Interface) and McBSP (Multichannel Buffered Serial Port), facilitating seamless interaction with a variety of peripheral devices. This ensures that the DSP can suit different application needs and integrate well into various system architectures.

Texas Instruments emphasizes low power consumption with the C64x DSPs, making them ideal for portable or energy-sensitive applications. Advanced power management techniques and technologies, such as dynamic voltage and frequency scaling, are incorporated to further enhance energy efficiency without compromising performance.

In summary, the Texas Instruments TMS320C64x DSP family stands out due to its high-performance capabilities driven by a VLIW architecture, high clock speeds, extensive memory options, a rich instruction set, and advanced connectivity features, all while maintaining power efficiency. These characteristics make it an exceptional choice for developers looking to integrate robust digital signal processing into their applications, whether in telecommunications, audio and video processing, or embedded control systems.
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