ZR36057 ZORAN [Zoran Corporation], ZR36057 Datasheet - Page 21

• Manufacturer Part Number: ZR36057
• Description: ENHANCED PCI BUS MULTIMEDIA CONTROLLER
• Manufacturer: ZORAN [Zoran Corporation]

mand” information, written by the host, for the next available
b u f f e r . T a b l e 1 0 s h o w s t h e i n t e r p r e t a t i o n f o r t h i s
c a s e .
Table 10: STAT_COM entry content, when
STAT_BIT=0
If the STAT_BIT=‘1‘, the content of the entry is the “status” infor-
mation, written by the ZR36057, of the most recently processed
field or frame. Table 11 shows the interpretation for this case.
Table 11: STAT_COM entry content, when
STAT_BIT=1
9.2 Fragment Table
The Fragment Table defines the structure of the allocated
memory for each code buffer. The table has N entries for N allo-
cated fragments. Each entry holds two doublewords:
The l.s. bit of the second doubleword is the FINAL bit, indicating
(when ‘1’) that the current fragment entry defines the last
fragment of the buffer.
9.3 JPEG Compression Modes
The sequence of actions performed by the host software and the
ZR36057 is as follows:
31:2
• first doubleword - the physical address of the fragment (must
• second doubleword - the fragment length in doublewords
31:24
22:1
Bit
Bit
23
1
0
0
be doubleword aligned),
(must be doubleword aligned).
FRAG_TAB_PTR[31:2]
FRAG_TAB_PTR [1]
STAT_BIT
F_CNT[7:0]
F_LENGTH[21:0]
STAT_BIT
Content
Content
The serial number, modulo 256, of the
most recent field or frame. Used in
compression only.
Reserved, set to ‘0’.
The length of the most recently com-
pressed field or frame in bytes, used in
compression only. The length is dou-
bleword aligned, so bits 2..1 are
always ‘0‘.
‘1‘, indicating that this table entry is a
status written by the ZR36057.
The address pointer to the
fragment table of the next buffer
to be used. The 2 l.s. bits of the
address must be ‘0’ - that is, the
address must be doubleword
aligned.
Must to be ‘0‘.
Must be ‘0’ to indicate that the
table entry is a command.
Description
Description
Enhanced PCI Bus Multimedia Controller
21
Several scenarios might cause a field or frame process to be
unsuccessful:
After an unsuccessful field/frame process in compression, the
ZR36057 does not issue an interrupt, and restarts with the next
field or frame.
9.4 JPEG Decompression Modes.
The sequence of actions performed by the host software and the
ZR36057 is as follows:
• The host allocates the first four code buffers and writes out
• The host loads the ZR36057’s I_STAT_COM_PTR register
• After the start of the compression process, the ZR36057
• After successfully completing transfer of the compressed
• If a new code buffer is unavailable at the beginning of a field
• When the host receives the interrupt, it checks the
• The allocated code buffer memory was smaller than the ac-
• A ZR36016 strip memory overflow occurs during the field/
• The host allocates the first four code buffers and writes out
• The host fills the allocated fragments with the code to be
• The host loads the ZR36057’s I_STAT_COM_PTR register
• After the start of the decompression process, the ZR36057
• After completing decompression of the field or frame, the
the code buffer table and the fragment table.
with the base address of the code buffer table.
starts filling the fragments of the first code buffer with the
compressed data of the first field or frame.
data of a field or frame, the ZR36057 writes the status infor-
mation back to the STAT_COM entry of the current buffer. It
sets the STATUS_BIT in the STAT_COM entry, declaring its
content as status. It then issues an interrupt, and starts the
next field or frame process.
or frame process (that is, if the STATUS_BIT of the next
buffer entry is ‘1’), the ZR36057 polls the STAT_COM entry
until the buffer is available.
STAT_COM entries in the code buffer table. For each entry
whose STAT_BIT=’1’, the host checks F_CNT to determine
whether any fields/frames were dropped. It records the code
buffer information, updates the fragment table and
STAT_COM entry of the code buffer, and returns it by reset-
ting STAT_BIT to ‘0’.
tual field/frame code volume (the ZR36057 fills the final
fragment, but the field/frame code transfer is not complete).
frame compression (might be caused by very large PCI bus
latency)
the code buffer table and the fragment table.
decompressed.
with the base address of the code buffer table.
starts reading the code of the first field or frame from the
code buffer fragments.
ZR36057 sets the STATUS_BIT in the STAT_COM register,