VIDEO INPUT

The video input (VI) unit reads digital video from an off-chip source,

demultiplexes the YUV data, subsamples as needed, and writes it to

SDRAM. Input is accepted from any CCIR656-compliant device that

outputs 8-bit parallel, 4:2:2 YUV time-multiplexed video data at up to

19 Mpix/sec. Such devices include digital video camera systems (which

can connect gluelessly to TM-1000) or devices connected through

ECL-level converters to the standard D1 parallel interface.

When needed, the VI unit can be programmed to perform on-the-fly

2X horizontal resolution subsampling. This enables high-resolution

images (640- or 720-pixels/line) to be captured and converted to 320-

or 360-pixels/line without burdening the CPU. When lower resolu-

tion video is eventually desirable, performing subsampling during data

capture can drastically reduce initial storage and bus bandwidth

requirements.

Useful in multiprocessor designs, the VI unit can also be used to

receive raw data and unidirectional messages from another TM-1000’s

video out port at up to 38 MB/sec.

VIDEO OUTPUT

Essentially, the TM-1000 video out (VO) unit performs the inverse

function of the VI unit. The VO generates an 8-bit, multiplexed YUV

datastream by gathering bits from the separate Y, U, and V data struc-

tures in SDRAM. It performs any programmed processing tasks then

outputs digital video data to off-chip video subsystems such as a digi-

tal video encoder chip, digital video recorder, or other CCIR656-com-

patible device. The VO unit outputs continuous digital video in arbi-

trary formats including PAL or NTSC at up to 40 Mpix/sec.

While generating the multiplexed stream, the VO unit can provide

optional horizontal 2X upscaling. For simultaneous display of pixel

graphics and live video, it can also generate sophisticated graphics

overlays with alpha blending of arbitrary size and position within the

output image.

The VO unit can either supply or receive video clock and/or synchro-

nizing signals from the external interface. Clock and timing registers

can be precisely controlled through programmable registers.

Programmable interrupts and dual buffers facilitate continuous data

streaming by allowing the CPU to set up a buffer while another is

being emptied by the VO unit.

Like the VI unit, the VO unit can also be used to pass raw data and

unidirectional messages from one TM-1000 to another.

Multimedia I/O and

coprocessing units

To streamline data throughput,

TM-1000 incorporates independent

DMA-driven multimedia I/O and

coprocessing units.These on-chip

units manage input, output, and

formatting of video, audio, graphics,

and communications datastreams

and perform operations specific to

key multimedia algorithms.