PNX1700EH,557 NXP Semiconductors, PNX1700EH,557 Datasheet - Page 803

• Manufacturer Part Number: PNX1700EH,557
• Manufacturer: NXP Semiconductors

Specifications of PNX1700EH,557

• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

Philips Semiconductors
Volume 1 of 1
8. System Endian Mode
PNX17XX_SER_1
Preliminary data sheet
Note that for indexed formats, each unit contains one or more pixels. For the packed
formats, a unit is a pixel, with the exception of packed YUV 4:2:2 where two units are
needed to describe a pixel pair.
Figure 13
The PNX17xx Series is designed to run either little-endian or big-endian software.
The entire system always operates in a single endian mode—i.e. the CPU and all
hardware subsystems run either little or big-endian. This is determined by a global
endian mode flag.
The endian mode determines how a multi-byte value is stored to/loaded from memory
byte addresses.
For the native pixel formats,
layout of a ‘unit’, which is always 8, 16 or 32 bits, and the mapping of adjacent units to
memory byte addresses. These two elements are always maintained, independent of
system endian mode.
What this implies is that each hardware subsystem needs to map a unit to memory
byte addresses in an endian mode-dependent manner. The rules are as follows:
Figure 13: Image Storage Format
•
•
•
•
•
•
•
pixel format, which implies the unit size(s)
origin pointer—the (byte) address of the first unit of the image
line pitch—the address difference between a pixel on a line and a pixel directly
below it
width W, in number of pixels
height H, in number of lines
origin
(a)
Storing a 16-bit unit to address ‘A’ results in modifying memory bytes ‘A’ and
‘A+1’
Storing a 32-bit unit to memory address ‘A’ results in modifying memory bytes ‘A’
to ‘A+3’
shows how images are stored in memory
linepitch
Rev. 1 — 17 March 2006
1unit
unit1 unit2
unit1 unit2
unit1 unit2
a
Section 3.
a+s
a+2s
unit3
unit3
unit3
. . . .
. . . .
W pixels
always shows two elements in the figures: the
. . . .
. . . .
. . . .
a+(k-1)s
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
unitk
unitk
unitk
Chapter 28: Pixel Formats
PNX17xx Series
1st line
2nd line
last line
H lines
28-12