Assembly Counter Square Wave gen and edge read

electric550 · 2009-07-17 07:16

So I wrote some code to see if my prop with an 8MHz and PLLX 16 crystal could output a 4MHz square wave from one pin to another then read it in with a counter in a different cog. The program was supposed to output 4000000 from the serial port if everything was working properly but it is not, I just get a bunch of letters....they do look consistent but... I am tired, and I can't figure out whats wrong with the code yet, so I figured I would see if anyone could see what was wrong. Any help is appreciated thanks!
I am sure will love the comments...Which might be wrong...just my thoughts on what is going on. Thanks again.


'This program is supposed to output 4MHz from pin 19 through a wire to pin 18
CON
     _clkmode = xtal1 + pll16x
     _xinfreq = 8_000_000

OBJ

 serial              : "fullduplexserialplus"

Var
long FourMHzGeneratorShare1                      'This variable is used to pass the desired square wave frequency to the assembly routine
long FourMHzReaderShare1                         'This variable is used to return the measured frequency from the assembly routine back to spin to send out serially to the terminal
Long Time                                        'Delay for Serial UpdateLOOP

 
Pub main

'Launch cogs to test the ability of Prop to generate and read 4 MHz square wave using counters @ 8MHz X 16

FourMHzGeneratorShare1 := 134217728              'This Value is used to generate the 4MHz square wave that is desired from formula on P137 PeLabsFunbook
cognew(@FourMHzGenerator,@FourMHzGeneratorShare1)'Start Cog to generate 4 MHz Square Wave, Also Pass in FourMHZGeneratorShare1 to share address of frequency value with assembly
cognew(@FourMHzReader,@FourMHzReaderShare1)      'Start Cog to Read Square Wave using counterA edge detection, Also Pass in FourMHzReaderShare1 to share value with spin
serial.start(31,30,0,1152000)                    'Start Serial terminal to send back the value read by the counter use tx and RX pins that are connected to USB
                                               
  repeat                                          'Repeatedly send the counted value out the serial port 
                                                    
    serial.dec(FourMHzReaderShare1)               'FourMHzReaderShare1 is the variable that reads the value from the memory address of the frequency value returned by the counting Cog
    waitcnt(Time += 1000000)                      '!!!THIS IS NOT PRINTing out 4million like I was hopeing:(

DAT
'-----------------------FourMHzGenerator------------------Derived from spin version from PElabFunbook v1.1 Page 140
              org    0                          'Begin at Cog RAM addr 0
FourMHzGenerator                                'begining of 4Mhz Generator Assembly Routine
                        mov     G0, Par          'Mov the hub address at which the desired frequency is stored from par into G0, Par comes from the second value that is passed in on Cog Init
                        rdlong  FO, G0           'Reads the value from hub memory location for desired oscillator Frequency and puts the long value in FO
                        or      dira, Pin19out   'Set Pin 19 to be an output, for the square wave generator output
                        mov     ctra, CtraNCO    'set CounterA to NCO/PWM single-ended   MOVI controls pins Page 207 PM 
                        mov     frqa, FO         'Pass in the Frequency to generate 4MHz from calculation from page 137 in FunBook
                                         

:LoopGen                                        'Infinite loop to continuously generate 4MHz square wave
                        jmp     #:LoopGen           'Continue to loop the 4Mhz Square Wave

              FIT
'---------------------FourMHzReader-----------------------------------------------------------------
              org 0                            'Begin at Cog RAM addr 0   
FourMHzReader           mov     G1, PAR        'First Line of FourMHzReader, Pass Global address int G0 from Par for Sharing Later P283
                        and     dira, Pin18in  'Make Pin 18 an input
                        mov     ctra, CtraNegEdge  'CounterA to NegEDGE detector, PLL divide by 1, Pin 18 as input Page10 Prop Data sheet
                        
                        mov     frqa, #1        'Start counting clock edges in increments of one
:LoopReader             mov     phsa, #0        'Make sure clock tick accumulator starts at zero before looping
                        mov     R0,  SecDelay   'store value to create a one second delay into R0 4cycles per instruction 128MHz 128/4 = 32M cycles 
:Delay1s                DJNZ R0, #:Delay1s        'loop onto itself untill 32M has decrimented to 0 then fall through this should take approximately one second
                        mov     FV, phsa        'move the accumulated clock ticks into FV
                        wrLong FV, G1           'Move FV value to Shared Memory Global mem assembly commands are backward
                        jmp #:LoopReader        'Jmp back to LoopReader to continue to measure the frequency


              FIT

'Declare Temporary and Specialized Variable for Assembly Code
        'R stands for register...similar to 8051 temporary registers
        R0              res     1
        R1              res     1
        R2              res     1
        'G stands for Global....This variable holds the address for global memory sharing
        G0              res     1               'G0 is used to pass in the hub address that contains the desired frequency of oscillation into the assembly program
        G1              res     1               'G1 is used to pass in the hub address to the pasm routine that will hold the measured frquency Value later the address is used to write the value to hub memory 
        'Below are specializer variables
        FO              res     1               'Frequency of Oscillation Value read from hub memory that sets the speed of the assemly routine square wave generator
        FV              res     1               'Frequency Value Returned from the counting assembly routine to the hub memory
        'These values are for masking
        Pin19out        long    %00000000_00000001_00000000_00000000
        CtraNCO         long    %00010011_10000000_00000000_00010011
        Pin18in         long    %11111111_11111111_01111111_11111111
        CtraNegEdge     long    %00111011_10000000_00000000_00010010
        'This is the value for looping
        SecDelay        long    32_000_000

Timmoore · 2009-07-17 07:27

res must be after everything else in a cog - the longs in your case.

I am not sure how the asm variables will work with the 2 cogs the offsets are goign to be different for the 2 cogs. I think you need to split the variables and put them before the fit of each cog.

ericball · 2009-07-20 12:55

First, RES must be the last entries in a cog routine.· RES is just a way to set a register # for a label without using any HUB RAM to do so.· Note - it will not be initialized and should not be accessed from SPIN code.

Second, any labels used in a cog routine must be before the next ORG (since the ORG resets the register #).

DAT
'-----------------------FourMHzGenerator------------------Derived from spin version from PElabFunbook v1.1 Page 140
              org    0                          'Begin at Cog RAM addr 0
FourMHzGenerator                                'begining of 4Mhz Generator Assembly Routine
                        rdlong  FRQA, PAR        'Reads the value from hub memory location for desired oscillator Frequency and puts the long value in FO
                        or      dira, Pin19out   'Set Pin 19 to be an output, for the square wave generator output
                        mov     ctra, CtraNCO    'set CounterA to NCO/PWM single-ended   MOVI controls pins Page 207 PM 
:LoopGen                                        'Infinite loop to continuously generate 4MHz square wave
                        jmp     #:LoopGen           'Continue to loop the 4Mhz Square Wave
        Pin19out        long    1<<19
        CtraNCO         long    %00100<<26+19
              FIT
'---------------------FourMHzReader-----------------------------------------------------------------
              org 0                            'Begin at Cog RAM addr 0   
FourMHzReader
                        andn    dira, Pin18in  'Make Pin 18 an input
                        mov     ctra, CtraNegEdge  'CounterA to NegEDGE detector, PLL divide by 1, Pin 18 as input Page10 Prop Data sheet
                        
                        mov     frqa, #1        'Start counting clock edges in increments of one
:LoopReader             mov     phsa, #0        'Make sure clock tick accumulator starts at zero before looping
                        mov     R0,  SecDelay   'store value to create a one second delay into R0 4cycles per instruction 128MHz 128/4 = 32M cycles 
:Delay1s                DJNZ    R0, #:Delay1s   'loop onto itself untill 32M has decrimented to 0 then fall through this should take approximately one second
                        wrLong  PHSA, PAR       'Move the accumulated clock ticks to Shared Memory Global mem assembly commands are backward
                        jmp     #:LoopReader    'Jmp back to LoopReader to continue to measure the frequency
        SecDelay        long    32_000_000
        Pin18in         long    1<<18
        CtraNegEdge     long    %01110<<26+18
        R0              res     1
              FIT

I have made some slight changes to remove unnecessary temporary variables and improve readability.· (Note: I don't think you had your pins set correctly.· I have matched the comments, not the values.)· You could, arguably, replace the MOV CTRA with MOVI CTRA, #CTRMODE·+ MOVS CTRA, #APIN for greater readability & no increase in code size.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Composite NTSC sprite driver: Forum
NTSC & PAL driver templates: ObEx Forum
OnePinTVText driver: ObEx Forum

electric550 · 2009-07-23 02:48

Thanks I will have to give this a try! Oh and I ended up writting some code to test the counters with 8 Mhz clock and the counters seem to operate. I have not checked how accurately but the led blinkss welll.. Anyways I will check this code out and see how it goes.
Thanks again!

hinv · 2009-07-23 04:00

That(the overclocking) was my first guess, without actually looking at the code. You might want to look at the posts bySapieha that describe the need for decoupling capacitors to handle the transient spikes, which will be much different in a visually perceivable LED blink.
Here it is http://forums.parallax.com/forums/default.aspx?f=25&m=361627

Assembly Counter Square Wave gen and edge read

Comments