p8x32a Parallax, Inc., p8x32a Datasheet - Page 15

• Manufacturer Part Number: p8x32a
• Description: 8-cog Multiprocessor Microcontroller
• Manufacturer: Parallax, Inc.

Propeller™ P8X32A Datasheet
As shown in Figure 6, The character pairs are merged
row-by-row such that each character's 16 horizontal pixels
are spaced apart and interleaved with their neighbors' so
that the even character takes bits 0, 2, 4, ...30, and the odd
character takes bits 1, 3, 5, ...31. The leftmost pixels are in
the lowest bits, while the rightmost pixels are in the
highest bits. This forms a long for each row of pixels in
the character pair. 32 such longs, building from top row
down to bottom, make up the complete merged-pair
definition. The definitions are encoded in this manner so
that a cog’s video hardware can handle the merged longs
directly, using color selection to display either the even or
the odd character.
Some character codes have inescapable meanings, such as
9 for Tab, 10 for Line Feed, and 13 for Carriage Return.
These character codes invoke actions and do not equate to
static character definitions. For this reason, their character
definitions have been used for special four-color
characters. These four-color characters are used for
drawing 3-D box edges at run-time and are implemented
as 16 x 16 pixel cells, as opposed to the normal 16 x 32
pixel cells. They occupy even-odd character pairs 0-1, 8-
9, 10-11, and 12-13.
Note 1: Only accessible as a source register (i.e. MOV Dest, Source).
Note 2: Only readable as a Source Register (i.e. MOV Dest, Source); read-modify-write not possible as a Destination Register.
Note 3: Reserved for future use.
Copyright © Parallax Inc.
Cog RAM Map
Table 15: Cog RAM Special Purpose Registers
Address
$1F0
$1F1
$1F2
$1F3
$1F4
$1F5
$1F6
$1F7
$1F8
$1F9
$1FA
$1FB
$1FC
$1FD
$1FE
$1FF
Page 15 of 36
Name
PAR
CNT
INA
INB
OUTA
OUTB
DIRA
DIRB
CTRA
CTRB
FRQA
FRQB
PHSA
PHSB
VCFG
VSCL
5.1.4.
Base-2 Log and Anti-Log tables, each with 2048 unsigned
words, facilitate converting values to and from exponent
form to facilitate some operations; see the Propeller
Manual for access instructions.
provides 2049 unsigned 16-bit sine samples spanning 0°
to 90° inclusively (0.0439° resolution).
5.2.
As stated in Section 4.3, the Cog RAM is used for
executable code, data, and variables, and the last 16
locations serve as interfaces to the System Counter, I/O
pins, and local cog peripherals (see Table 15).
When a cog is booted up, locations 0 ($000) through 495
($1EF) are loaded sequentially from Main RAM / ROM
and its special purpose locations, 496 ($1F0) through 511
($1FF), are cleared to zero. Each Special Purpose register
may be accessed via its physical address, its predefined
name, or indirectly in Spin via a register array variable
SPR with an index of 0 to 15, the last four bits of the
register's address.
Type
Read-Only
Read-Only
Read-Only
Read-Only
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Math Function Tables
Cog RAM
1
1
1
1
2
2
Description
Boot Parameter
System Counter
Input States for P31 - P0
Input States for P63- P32
Output States for P31 - P0
Output States for P63 – P32
Direction States for P31 - P0
Direction States for P63 - P32
Counter A Control
Counter B Control
Counter A Frequency
Counter B Frequency
Counter A Phase:
Counter B Phase
Video Configuration
Video Scale
Figure 6
Propeller Character
Interleaving
Also, a sine table
Rev 1.0 11/14/2007
www.parallax.com
3
3
3