comtech aha corporation
Figure 1: AHA3410C Block Diagram
FUNCTIONAL DESCRIPTION
The coprocessor device has three external high
speed synchronous data ports each capab le of
transferring once every 25 MHz clock. These are a
32-bit bidirectional data port, an 8-bit Video Input
Data (VID) port and a Video Output Data (VOD)
port. The 32-bit port is capable of transferring up to
100 MBytes/sec. The VID and VOD are capable of
up to 25 MBytes/sec each.
The device accepts uncompressed data through
the 32-bit data or optionally through the 8-bit VID
port into its Compression In FIFO (CI FIFO). The
32-bit data port may be configured for 16-bit
transfers. Compressed data is available through the
32-bit data port via the Compressed Output FIFO
(CO FIFO). The sustained data rate through the
compression engine is 25 MBytes/sec.
Decompression data may be simultaneously
processed by the device. Decompression data is
accepted through the 32-bit data port, buf fered in the
Decompression Input FIFO (DI FIFO), and
decompressed. The output data is made available on
the 32-bit data port via the Decompression Output
FIFO (DO FIFO) or optionally on the 8-bit Video
Output port. The decompression engine runs on the
25 MHz clock and is capable of processing an
uncompressed byte ev ery clock, i.e. 25 MBytes/sec.
The four FIFOs are organized as 16x32 each.
For data transfers through the three ports, the
“effective” FIFO widths differ according to their
data bus widths.
Data transfer for compression or decompres-
sion is synchronous over the three data ports
functioning as DMA masters. To initiate a transfer
into or out of the Video ports, the device asserts
VxREQN, the external device responds with
VxACKN and begins to transfer data over the VID
or VOD busses on each succeeding rising edge of
the clock until VxREQN is deasserted. The 32-bit
port relies on the FIFO Threshold settings to deter-
mine the transfer.
SYSTEM APPLICATION
The device is intended for memory intensive
applications, such as high resolution copiers or
printers. These applications require the simulta-
neous compression and decompression capability
of the device. Copiers use this feature to feed the
compressed bit maps through the decompressor to
the printer engine while another process uses the
compressor to input and co mpress scanned images.
Movement for both processes is typically controlled
by a DMA controller that is programmed by the
local microprocessor or by programmed I/O.
(From Scanner)
VIREQN
VID[7:0]
VIACKN
D[31:0]
DRIVEN
TEST
CLK
RSTN
PROCMODE[1:0]
PD[7:0]
PA[4:0]
CSN
DIR
RDYN
INTRN
VOACKN
VOD[7:0]
VOREQN
VOEORN
(To Printer)
COEORN
DOREQN
COREQN
DIREQN
CIREQN
SD
DOACKN
COACKN
DIACKN
CIACKN
VID
PORT
DATA
PORT
CI
FIFO
16x32
DI
FIFO
16x32
CLOCK
DATA PORT CONTROL
COMPRESSOR
DECOMPRESSOR
MICROPROCESSOR INTERFACE
CO
FIFO
16x32
DO
FIFO
16x32
VOD
PORT
AHA3410C
StarLite
8
8 8
888
32
32 32
5
8