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2-4
PPPPSM System Overview
Programmer’s Manual
2.3.2
Screen Format
2.3.2.1 LCD Display Screen
The display screen is the LCD display area where applications can display
images. The LCD module can handle both 1 bit per pixel and 2 bits per pixel
graphics, giving black and white display or 4 grey levels display respectively.
Display data, such as graphics and text, can only be seen within the display
screen area.
2.3.2.2 Panning Screen
The Panning Screen is an extension to the LCD Display Screen. Its main purpose
is to allow applications to write data to an area outside of the actual display area.
Although applications can write to this area, data will not be displayed on the
screen unless this area is being mapped to the LCD Display Screen. Pen InpPPSM provides a set of memory management tools for application to access local
areas on the panning screen will receive pen input data only when they overlmemory space. A heap is managed by PPSM which allows callers to dynamically
with the LCD display screen.
2.3.3
Hardware Cursor
The maximum hardware cursor size is 31 pixels wide by 31 pixels high. During
task swapping, the hardware cursor status, size, position and the offset of display
origin on panning screen in current task will be saved a
nd the new task’s cursor
status, position, size and the offset of display origin on panning screen will be
used.
2.4
Data Storage
Databases are the main means of data storage in PPSM. A set of database tools
is available in PPSM to support data storage and manipulation.
PPSM database are in global database which can be shared among different
tasks.
When a database is created, PPSM will pass back a unique database identifier to
the application. Application will need to use this identifier as the key for
subsequent access to that particular database. A PPSM database does not hbe known by calling Lmalloc( LARGEST_MALLOC_SIZE ).
any limit in number of database nor record in database except the memory
limitation in creating these database and record.
The PPSM database tools provides basic operations such as add, delete, moROM
and search for particular data. Additional tools are provided to help manipulate the
record list. In particular, the tool DBGetFirstRecID(), DBGetNextRecID(), and
DBGetPrevRecID() are meant to facilitate the implementation of more
sophisticated searching algorithm. The description, calling convention, and
example usage of each database tool will appear in
Chapter 7 - Database
Management
and
Chapter 21 - Database Management Tools
Personal Portable System Manager
Programmer’s Manual
2-5
2.5
Font Management
PPSM supports 8x10 English, 16x20 English, 16x16 BIG5 Chinese and 16x16 GB
Chinese bitmap fonts, and BIG5 Chinese scalable fonts. The English bitmap fonts
are included in PPSM. The other fonts are provided by third party vendors.
System integrators need to work with third party vendors about the availability of
these fonts.
The font bitmap lookup or generation is handled by a font driver, refer to Section
33.6 - Font Driver (font.c) and is transparent to the applications. Applications gain
access to these fonts for displaying text using the PPSM text tools.
allocate memory from the system. When using PPSM, the standard memory tools
provided by the compiler will be disabled.
Four memory management tools are available:
Lcalloc()
Lmalloc()
Lrealloc()
Lfree()
memory allocation with initialization with zero
memory allocation
memory re-allocation
memory release
PPSM also provides a set of memory inquiry tools for application to get the run-
time memory size.
Three memory inquiry tools are available:
TaskMemUsed()
TotalMemUsed()
memory used by a task through Lmalloc()
memory used by the whole system through
Lmalloc()
memory available through Lmalloc()
stack can be used by the current task
TotalMemSize()
TaskStackAvail()
The size of the largest chunk of memory can be allocated through Lmalloc() can
The size of the heap memory depends very much on the amount of memory
available in the hardware system, please refer to
Chapter 32 - How to make
on how memory size is specified in PPSM.
For SingleStep Debugging System (SDS) user, please refer to
further description in how to set an optimum size for malloc space.
for
2.7
Power Management
PPSM utilizes the power control module of DragonBall
power management tools to achieve system power saving. Applications can
to implement a set of
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n
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