/
PulseWidth.spin
109 lines (80 loc) · 4.76 KB
/
PulseWidth.spin
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{{
+-------------------------------------------------+
| JTAGulator |
| Pulse Width Detection Object |
| |
| Author: Joe Grand |
| Copyright (c) 2020 Grand Idea Studio, Inc. |
| Web: http://www.grandideastudio.com |
| |
| Distributed under a Creative Commons |
| Attribution 3.0 United States license |
| http://creativecommons.org/licenses/by/3.0/us/ |
+-------------------------------------------------+
Program Description:
This object measures and stores the negative-going
pulse widths (high-low-high) of a signal on the
specified input pin.
}}
CON 'offsets of the structure below
RXPIN_OFF = 0
RCVCNT_OFF = 4
SAMPLEBUFFER_OFF = 8
VAR
long cog ' Used to store ID of newly started cog
long rxPin ' Parameters used by cog
long rcvCnt
long sampleBuffer
PUB Start(pin, count, bufptr): okay 'Start a new cog with the assembly routine
Stop
rxPin := pin ' Pin to measure
rcvCnt := count ' Number of samples to receive/have received
sampleBuffer := bufptr ' Address of global buffer from top object
okay := cog := cognew(@Init, @rxPin) + 1
PUB Stop 'Stop the currently running cog, if any
if cog
cogstop(cog~ - 1)
dat ' assembly program
org 0
Init
mov rx_pin, par ' start of the structure
add rx_pin, #RXPIN_OFF
rdlong rx_pin, rx_pin ' point to the variable passed into the cog
mov rx_mask, #1
shl rx_mask, rx_pin ' create bit mask for desired pin
andn dira, rx_mask ' make rx pin an input
mov rcv_cnt, par
add rcv_cnt, #RCVCNT_OFF
rdlong rcv_cnt, rcv_cnt ' point to the variable passed into the cog
mov buf_ptr, par
add buf_ptr, #SAMPLEBUFFER_OFF
rdlong buf_ptr, buf_ptr ' point to the variable passed into the cog
rdlong t1, rcv_cnt ' number of samples to receive
mov t2, #0 ' clear count
wrlong t2, rcv_cnt ' number of samples received
movi ctra, #%01100_000 ' NEG detector
movs ctra, rx_pin ' pin to measure
mov frqa, #1 ' phsa increments by 1 when apin = LOW
Measure
cmp t1, t2 wz ' if we've reached the desired sample count
if_e jmp #Done ' then finish
waitpne rx_mask, rx_mask ' wait for pin low
mov phsa, #0
waitpeq rx_mask, rx_mask ' wait for pin high
mov phsa, phsa
add phsa, #9 ' offset to account for mov
wrlong phsa, buf_ptr ' store pulse width into the buffer
add buf_ptr, #4 ' increment buffer index
add t2, #1 ' increment sample counter
wrlong t2, rcv_cnt
jmp #Measure
Done ' infinite loop until the cog is stopped by top object
jmp #Done
' VARIABLES stored in cog RAM (uninitialized)
rx_pin res 1 ' rx pin
rx_mask res 1 ' mask for rx pin
rcv_cnt res 1 ' sample counter
buf_ptr res 1 ' pointer for result
t1 res 1
t2 res 1
fit ' make sure all instructions/data fit within the cog's RAM