RM0082
LS_JPEG codec
Doc ID 018672 Rev 1
555/844
25 LS_JPEG
codec
25.1 Overview
Within its Low Speed Connectivity Block, the device provides a
JPEG Codec
with header
processing which is built around existing JPEG ECS CODEC and extends its functionality by
providing additional support for JPEG Header parsing and generation.
The encoding process compresses 8x8 pixel blocks (data units) into either a complete
JPEG encoded output stream or only ECS data depending on whether the header
processing functionality of the core is enabled.
The decoding process can either decode a complete JPEG encoded data stream or an input
data stream with only ECSs. In either case, the core decodes the ECS data into valid 8 x 8
pixel blocks (data units).
Main features of the JPGC are:
●
Compliance with the baseline JPEG standard (ISO/IEC 10918-1).
●
Single-clock per pixel encoding/decoding.
●
Support for up to four channels of component color.
●
8 bit/channel pixel depths.
●
Programmable quantization tables (up to four).
●
Programmable Huffman tables (two AC and two DC).
●
Programmable Minimum Coded Unit (MCU).
●
Configurable JPEG headers processing.
●
Support for restart marker insertion.
●
Use of two DMA channels (from the Basic Subsystem) and of two 8 x 32 bits FIFO’s
(local to the JPGC) for efficient transferring and buffering of encoded/decoded data
from/to the Codec Core.
25.2 Signal
interfaces
The JPGC directly interfaces with the signals summarized in
. The JPGC is
connected as a slave on the AHB bus, and has two DMA channels asserted to itself. A
functional diagram of these signal interfaces is given in
Table 467.
GPIO signal interface
Group
Signal name
Direction
Size
(bit)
Description
AHB Slave
-
Input/Output -
See AMBA specification.
DMAC
-
Input/Output -
See