122-32000 Parallax Inc, 122-32000 Datasheet - Page 30

• Manufacturer Part Number: 122-32000
• Description: MANUAL PROPELLER
• Manufacturer: Parallax Inc

Specifications of 122-32000

• Accessory Type: Manual
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Locks
There are eight lock bits (also known as semaphores) available to facilitate exclusive access
to user-defined resources among multiple cogs. If a block of memory is to be used by two or
more cogs at once and that block consists of more than one long (four bytes), the cogs will
each have to perform multiple reads and writes to retrieve or update that memory block. This
leads to the likely possibility of read/write contention on that memory block where one cog
may be writing while another is reading, resulting in misreads and/or miswrites.
The locks are global bits accessed through the Hub via the Hub Instructions:
LOCKRET
cog at a time can affect them, making this an effective control mechanism. The Hub
maintains an inventory of which locks are in use and their current states, and cogs can check
out, return, set, and clear locks as needed during run time. See
LOCKSET
Main Memory
The Main Memory is a block of 64 K bytes (16 K longs) that is accessible by all cogs as a
mutually-exclusive resource through the Hub. It consists of 32 KB of RAM and 32 KB of
Page 30 · Propeller Manual v1.0
CLKSELx
2
0
0
0
0
1
1
1
1
1
0
0
1
1
0
0
1
1
,
, 234; and
LOCKSET
0
0
1
0
1
0
1
0
1
XTALx and PLL16x
XTALx and PLL1x
XTALx and PLL2x
XTALx and PLL4x
XTALx and PLL8x
_CLKMODE
, and
RCSLOW
LOCKCLR
RCFAST
Setting
XINPUT
LOCKCLR
, 228 for more information.
Table 1-10: CLKSELx (Bits 2:0)
. Because locks are accessed only through the Hub, only one
~12 MHz
XIN x 16
~20 kHz
Master
XIN x 1
XIN x 2
XIN x 4
XIN x 8
Clock
XIN
OSC+PLL OSCENA and PLLENA must be '1'.
OSC+PLL OSCENA and PLLENA must be '1'.
OSC+PLL OSCENA and PLLENA must be '1'.
OSC+PLL OSCENA and PLLENA must be '1'.
OSC+PLL OSCENA and PLLENA must be '1'.
Source
Internal
Internal
OSC
No external parts.
May range from 8 MHz to 20 MHz.
Very low power.
May range from 13 kHz to 33 kHz.
OSCENA must be '1'.
LOCKNEW
Notes
, 230;
LOCKRET
LOCKNEW
, 233;
,