ZR36057 ZORAN [Zoran Corporation], ZR36057 Datasheet - Page 44

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

Enhanced PCI Bus Multimedia Controller
Appendix A: ZR36100 - ZR36057 Interface
Figure 15 describes a recommended interconnection between
the ZR36057 and the ZR36100 / ZR36110 host bus.
ZR36100 Reset
Any of the software controlled GPI/O pins (configured as output)
of the ZR36057 may be used as a RESET input of the decoder.
The software then directly manipulates the RESET signal
through the corresponding register bit. Since the default config-
uration of the GPIO pins after reset is input, a pull down resistor
should be applied to the ZR36100 RESET input.
Mapping the ZR36100 on the ZR36057’s GuestBus
The driver software must map the ZR36100 on the GuestBus:
the ZR36100 ’s guest ID number (0,1,2, or 3) must be configured
as a code-write target. The proper timing parameters (tdur = 3,
to ensure 82ns, trec = 4, to ensure 100ns) of the ZR36100 must
be loaded to the GuestBus control register (address 0x030). The
ZR36100 occupies only four 8-bit registers out of the eight reg-
isters dedicated to each guest.
Figure 15. ZR36057 - ZR36100/110 Basic Interconnection
ZR36100/110
BUSADD[1:0]
BUSDAT[7:0]
BUSWR
BUSCS
BUSRD
READY
VSYNC
RESET
DREQ
DACK
IDLE
V
DD
(Optional)
(Optional)
Other Guests
GCSn
GWR
GRD
GADR[2:0]
GDAT[7:0]
GRDY
GIRQ0
GPIO0
GIRQ1
ZR36057
44
ZR36100 Initialization
The initialization consists of loading the ZR36100 microcodes
and parameters. This is done using the PostOffice mechanism.
The host interface of the ZR36100 must be set to 8 bit, Intel
format, I/O only. The BSLN parameter should be set to 2 or 4, for
efficient operation.
On-Line Commands and Status
On-line command writes and status reads are also done using
the PostOffice mechanism.
Bitstream Transfer
Some preparations must be done prior to triggering the
ZR36100 with a go command.
The host must allocate a contiguous code buffer in the system
memory. Bitstream retrieved from the MPEG source is stored in
this buffer. The ZR36057 reads data from this buffer in a DMA
fashion and transfers it, through the CFIFO, to the MPEG
decoder. There are several possible sizes of the memory buffer.
The host must inform the ZR36057 of the buffer address, size
and “report step”. After the code buffer in memory is allocated,
reported to the ZR36057, and filled up for the first time, a
ZR36100 go command can be issued. Immediately after this, the
DMA code-read cycles must be enabled by setting the DMA
Code-Read Enable bit to ‘1’. The ZR36057 then starts fetching
data from the main memory buffer using cyclic addressing.
Whenever it passes a “report step” it initializes an interrupt
request. Within the interrupt service routine the host should
check the current position of the ZR36057 Code Memory Buffer
Pointer, and decide weather it should refresh an old portion of
the buffer with new data from the MPEG source. Once the coded
data arrives at the CFIFO, the GBM unit starts writing it over the
GuestBus to the ZR36100 .