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| Parallax code award to Jim Coleman |
COG LOADER: LOADING COGS IN A PROPELLER CHIP
ONE of the most important functions in the Parallax Propeller chip is the ability to talk between various processors. There are numerous ways to write programs to do this, some which use a fractional number of the chip's eight cores and some programs which use the full load of cores. Some examples are spartan and some are more comprehensive and involved, and some will contain embedded comments while others have none. In these examples, cores are called Cogs, the naming convention conceived by the Propeller designer, Charles "Chip" Gracey III, who is also the founder of Parallax Company.
Let's take a look at these programming examples that can talk with Cogs. First up, we honor and spotlight Jim Coleman's award, Object of the Week, issued by Parallax this week. The program is found at the Obex and can be downloaded here. The program is fantastic in documentation and includes the use of PBASIC style language for the Propeller chip. Next up is this sample found at QuickStart 5: Multiple Cogs. It loads up three cogs with tasks that all run at the same time. The code is provided below.
CON
_clkmode = xtal1 + pll16x 'Establish speed
_xinfreq = 5_000_000 '80Mhz
OBJ
led: "E555_LEDEngine.spin" 'Include LED methods object
VAR
byte Counter 'Establish Counter Variable
long stack[90] 'Establish working space
PUB Main
cognew(Twinkle(16,clkfreq/50), @stack[0]) 'start Twinkle cog 1
cognew(Twinkle(19,clkfreq/150), @stack[30]) 'start Twinkle cog 2
cognew(Twinkle(22,clkfreq/100), @stack[60]) 'start Twinkle cog 3
PUB Twinkle(PIN,RATE) 'Method declaration
repeat 'Initiate a master loop
repeat Counter from 0 to 100 'Repeat loop Counter
led.LEDBrightness(Counter, PIN) 'Adjust LED brightness
waitcnt(RATE + cnt) 'Wait a moment
repeat Counter from 100 to 0 'Repeat loop Counter
led.LEDBrightness(Counter,PIN) 'Adjust LED brightness
waitcnt(RATE + cnt) 'Wait a moment
Next, move onto Methods & Cogs and follow the details of the Spin code shown below.
'' File: CogStartStopWithButton.spin
'' Launches methods into cogs and stops the cogs within loop structures that
'' are advanced by pushbuttons.
VAR
long stack[60]
PUB ButtonBlinkTime | time, index, cog[6]
repeat
repeat index from 0 to 5
time := ButtonTime(23)
cog[index] := cognew(Blink(index + 4, time, 1_000_000), @stack[index * 10])
repeat index from 5 to 0
ButtonTime(23)
cogstop(cog[index])
PUB Blink( pin, rate, reps)
dira[pin]~~
outa[pin]~
repeat reps * 2
waitcnt(rate/2 + cnt)
!outa[pin]
PUB ButtonTime(pin) : delta | time1, time2
repeat until ina[pin] == 1
time1 := cnt
repeat until ina[pin] == 0
time2 := cnt
delta := time2 - time1
PROPELLER LINK TREASURY
Parallax Inc.
http://www.parallax.com/
OBEX
http://obex.parallax.com/object/61
QuickStart 5: Multiple Cogs
http://www.parallaxsemiconductor.com/quickstart5
Propeller Education Kit Labs
http://www.parallax.com/go/pekit
Comstock's
https://www.comstocksmag.com/batteries-not-included
Propeller <-> PC Terminal Communication (forums)
http://forums.parallaxinc.com/forums/?f=25&m=341494&g=341494#m341494
Debug LITE for the Parallax Serial Terminal (forums)
http://forums.parallaxinc.com/forums/default.aspx?f=25&m=348893
Measure Resistance and Capacitance (forums)
http://forums.parallaxinc.com/forums/default.aspx?f=25&m=335407
Transmit Square Wave Frequencies (forums)
http://forums.parallaxinc.com/forums/default.aspx?f=25&m=343747
EEPROM Datalogging and I2C (forums)
http://forums.parallaxinc.com/forums/default.aspx?f=25&m=219237
Servo Control (forums)
http://forums.parallaxinc.com/forums/?f=25&m=197069&g=197069#m197069
PEKbot (forums)
http://forums.parallaxinc.com/forums/default.aspx?f=25&p=1&m=174962
Methods & Cogs
http://nagasm.org/ASL/Propeller/printedPDF/MethodsAndCogs-v10.pdf
