Enhanced PCI Bus Multimedia Controller
and “Gib” Endian formats are supported where applicable (Refer
to the PCI Multimedia Design Guide, Revision 1.0).
Compression (Decompression) mode. The Still Transfer port is
mapped inside the ASR area, and a special controller intercon-
nects this port to the ZR36057’s extended video bus (24 bits
RGB). The Still Transfer handshake protocol enables high rate
pixels transfer between the system memory and the JPEG pro-
cessor via the ZR36057.
4.2.2 Display Modes
The display mode can be configured to either emulated inter-
laced video (both input fields are displayed simultaneously on
the non-interlaced monitor) or single field display. The latter is
appropriate for motion artifact elimination when displaying live or
decompressed Motion JPEG video.
2
4.3.5 I C Port
2
2
A software-driven I C port allows controlling of I C devices.
4.2.3 Frame Grabbing
4.3.6 Interrupt Manager
The ZR36057 can grab video frames (scaled or non scaled), or
fields, in any of the pixel formats listed above, directly into
system memory, eliminating the need for memory on the add-in
board.
Interrupt requests associated with several internal and external
conditions are sent to the host via the PCI bus (using INTA).
Selection of interrupt originators is programmable.
4.4 Code DMA Controller
4.2.4 Overlay Control
The ZR36057 includes a DMA channel for transferring data
between the system memory and a selected device on the Code
Bus or GuestBus. Two configurations are supported:
Graphics overlay is supported, in that display memory areas that
are “owned” by graphics applications, may not be loaded with
video pixels, allowing true windowing and overlay. The software
driver prepares a masking map of the video rectangle, and the
ZR36057 uses this map for masking decision, when transferring
the pixels to the display memory.
• MPEG mode. The data flow is unidirectional, from the sys-
tem memory, to the ZR36057’s GuestBus.
• JPEG mode. The data flow is bidirectional, and the direction
is determined by the selected sub-mode. In JPEG Compres-
sion, the data flows from the Codec bus to the system
memory. In JPEG Decompression, the data flows from the
system memory to the Codec bus.
4.3 Host Control/Communication Services
4.3.1 Application-Specific Registers (ASRs)
The name “application-specific” distinguishes these registers
from the PCI configuration space registers. These memory
mapped registers provide the host software with full control over
the operation of the ZR36057. The ZR36057 claims a contigu-
ous space of 4 KBytes in system memory.
4.4.1 MPEG Mode
In MPEG mode, the data flows from the system memory to the
ZR36057’s GuestBus. Typically, this would be a compressed bit-
stream, to be decompressed by a device such as an MPEG
decoder attached to the GuestBus. Other examples are sampled
audio (WAV data), MIDI token stream, etc. Temporary latencies
on the PCI bus or the GuestBus are handled without loss of data.
4.3.2 GuestBus
Host software control over non-PCI devices, such as a Motion
JPEG codec, an MPEG decoder, a video encoder, etc., is done
through the ZR36057’s GuestBus. Host accesses to these
“guest” devices, mapped as application specific registers inside
the ZR36057, are output as GuestBus cycles. Such accesses
can either use the PostOffice handshaking protocol, or the Code
DMA Controller. The first method is adequate for commands,
configuration data, etc., while the second method provides a
faster channel, and is intended for continuous transfer of data
such as a compressed bitstream.
The GuestBus master simultaneously serves the PostOffice
accesses and the code DMA transfers: DMA transfers are
viewed as the “main” task of the GuestBus master, while any
number of PostOffice requests may occasionally interrupt the
DMA traffic.
The DMA controller supports both auto-initialized (cyclic) block
transfers, or single block transfers. The size of the destination
block in main memory can be selected out of several possible
sizes, ranging from 8 KBytes up to 256 KBytes. The destination
block may also be virtually split into several sub-blocks, allowing
the ZR36057 to interrupt the host when a sub-block has been
transferred. This feature provides the software with a means of
optimizing the refill accesses according to the application
requirements and the disk performance.
4.3.3 PostOffice Handshaking Protocol
The ZR36057 PostOffice handshaking protocol, implemented
over the GuestBus, allows host accesses to relatively slow guest
devices, with no degradation of the PCI bus performance.
4.3.4 Still Transfer Mechanism
4.4.2 JPEG Modes
The ZR36057 supports a dedicated Still Transfer port, by means
of which the host writes (reads) image pixels in JPEG Still Image
In the JPEG modes, the data flows between the system memory
and the ZR36057’s Codec bus. In JPEG Compression, from the
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