PropBOE ADC with the Propeller Activity Board
Jkane
Posts: 113
Hello,
first of all the propeller activity is a great board,
what i am trying to do is fairly simple (of course it does not work so ......)
I'm trying to run the A/D on the propeller activity board (0,1,2,3), (bottom right of board)
when i run the program below and connect AD1 to ground, I think I should show 0 volts (Vss), and if it connect it to 3.3 (Vdd) I should get 3.3 volts and so on
all i get is:
Starting ADC Program
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
my code:
and the Prop BOE ADC code is:
first of all the propeller activity is a great board,
what i am trying to do is fairly simple (of course it does not work so ......)
I'm trying to run the A/D on the propeller activity board (0,1,2,3), (bottom right of board)
when i run the program below and connect AD1 to ground, I think I should show 0 volts (Vss), and if it connect it to 3.3 (Vdd) I should get 3.3 volts and so on
all i get is:
Starting ADC Program
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
ad=-1
my code:
Con
_clkmode = xtal1 + pll16x
_xinfreq = 5_000_000 'Set to standard clock mode and frequency (80 MHz)
obj
system : "Propeller Board of Education"
'pst : "Parallax Serial Terminal"
pst : "Parallax Serial Terminal"
adc : "PropBOE ADC"
time : "Timing"
var
long ad
Pub Go
system.Clock(80_000_000)
pst.Start(115_200)
pst.clear
pst.Str(String("Starting ADC Program ",pst#NL))
repeat
ad := adc.In(1)
Display
'pst.Str(String("Starting ADC Program ",pst#NL))
waitcnt(cnt + (1 * clkfreq))
Pub Display
'pst.Home
pst.Str(String("ad="))
pst.Dec(ad)
pst.Str(String(" ",pst#NL))
'pst.Clear
and the Prop BOE ADC code is:
{{Input Output Pins.spin
This object measures voltage at the A0, A1,
A2 or A3 sockets. Its In method returns
a value from 0 to 1023, representing the
number of 1024ths of 5 V applied the socket.
Example Program with adc Nickname
┌───────────────────────────────────────────────┐
│ ''Displays measurement from A3 input │
│ ''as number of 1024ths of 5 V. │
│ │
│ OBJ │
│ │
│ system : "Propeller Board of Education" │
│ adc : "PropBOE ADC" │
│ pst : "Parallax Serial Terminal Plus" │
│ │
│ PUB Go | adcVal │
│ │
│ system.Clock(80_000_000) ' Clock -> 80 MHz │
│ │
│ adcVal := adc.In(3) 'Measure A3 │
│ pst.Dec(adcVal) 'Display value │
│ '(1024ths of 5 V) │
└───────────────────────────────────────────────┘
NOTE This object samples at a maximum
of 1.16 ksps. The ADC is can
sample at rates up to 24 kHz with
the PropBOE ADC (ASM).spin object.
This object has a few updates
pending before it can be added to
this package. Expected release
date is May 1, 2012.
BUGS Please send bug reports,
& questions, suggestions,
UPDATES and improved versions of this
object to [EMAIL="alindsay@parallax.com"]alindsay@parallax.com[/EMAIL],
and check back periodically for
updated versions.
}}
VAR
long configured, started
long adc[4]
long cog, stack[32], lockID
OBJ
i2c : "I2C Slave 7bit"
PUB Start(chlist) : success
{{Optional method, not required for A/D measurements
If your code calls this before the first call to the In
method, it will launch the A/D conversion process into
another cog. The advantage here is a 2x sampling rate
increase, but it's still only 1.16 ksps for 1 channel,
0.558 ksps for 2 channels, etc.
For sampling rates up to 22 ksps, use the
PropBOE ADC (ASM) object instead. See NOTE section at
the start of the file for more info.
Parameters:
chlist - Binary value that represents which channels
to sample. For example if you set chlist to
%0101, it will repeatedly sample channels
2 and 0. %1010 will repeatedly sample
channels 3 and 1. %1111 will sample all the
channels, %0001 will sample only channel 0,
and so on...
Returns:
success - Returns a value in the 1 to 8 range if it
successfully launched a cog, or 0 if no cogs
or locks are available.
}}
if (lockID := locknew) == -1
return success := false
success := cog := (cognew(AdcLoop(chlist), @stack) + 1)
PUB Stop
{{Stops the A/D conversion process and frees a cog and
a lock bit. You can still call the In method after calling
this method. The only difference is that the cog that
calls the In method will be the cog that also does the A/D
conversion at a slightly slower rate.}}
if cog
cogstop(cog~ - 1)
lockret(lockID)
PUB In(channel) : adcval | pointer, acks, chan
{{Measure input voltage at one of the Propeller Board
of Education's analog inputs: A0, A1, A2 are sockets
below the breadboard, and A3 is connected to an
amplified microphone output.
Parameter: channel use 0, 1, 2, or 3 for A0, A1, A2,
or A3}}
ifnot configured
i2c.Init(29, 28, %010_0011)
ifnot cog
pointer := |< (channel + 4)
acks := i2c.poll(0)
acks += i2c.ByteOut(pointer)
acks += i2c.poll(1)
adcval := i2c.ByteIn(0)
chan := adcval>>4
adcval &= %1111
adcval <<= 8
adcval += i2c.ByteIn(1)
adcval >>= 2
if acks <> 0 or chan <> channel
adcval := -1
else
repeat until not lockset(lockID)
adcVal := adc[channel]
lockclr(lockID)
PRI AdcLoop(chlist) | pointer, acks, chan, idx, list, i
{{Measure input voltage at one of the Propeller Board
of Education's analog inputs: A0, A1, A2 are sockets
below the breadboard, and A3 is connected to an
amplified microphone output.
Parameter: channel use 0, 1, 2, or 3 for A0, A1, A2,
or A3.
}}
ifnot configured
i2c.Init(29, 28, %010_0011)
pointer := (chList << 4)
acks := i2c.poll(0)
acks += i2c.ByteOut(pointer)
acks += i2c.poll(1)
repeat
list := chList
repeat i from 0 to 3
if list & 1 == 1
repeat until not lockset(lockID)
adc[i] := i2c.ByteIn(0)
chan := adc[i] >> 4
adc[i] &= %1111
adc[i] <<= 8
adc[i] += i2c.ByteIn(0)
adc[i] >>= 2
if acks <> 0 or chan <> i
adc := -1
lockclr(lockID)
list >>= 1
PUB Config(sda, scl, addr)
{{You do not need to call this method if you are using
a Propeller Board of Education.
Optional configuration method for using the AD7993 with
other boards (not Propeller BOE). If you are using the
Propeller BOE, there's no need to call this method. If
you are configuring the ADC to a different set of I/O
pins, call this method before calling Start or In
methods.
Parameters: sda - Propeller I/O pin connected to I2C
serial data pin
scl - Propeller I/O pin connected to I2C
serial clock pin
addr - I2C address the AD7993 is set to
See AD7993 datasheet info on setting
the chip's I2C address.
}}
configured := sda << 24 + scl << 16 + addr <<1
DAT
{{
File: PropBOE ADC.spin
Date: 2012.03.19
Version: 0.32
Author: Andy Lindsay
Copyright: (c) 2012 Parallax Inc.
┌────────────────────────────────────────────┐
│TERMS OF USE: MIT License │
├────────────────────────────────────────────┤
│Permission is hereby granted, free of │
│charge, to any person obtaining a copy │
│of this software and associated │
│documentation files (the "Software"), │
│to deal in the Software without │
│restriction, including without limitation │
│the rights to use, copy, modify, merge, │
│publish, distribute, sublicense, and/or │
│sell copies of the Software, and to permit │
│persons to whom the Software is furnished │
│to do so, subject to the following │
│conditions: │
│ │
│The above copyright notice and this │
│permission notice shall be included in all │
│copies or substantial portions of the │
│Software. │
│ │
│THE SOFTWARE IS PROVIDED "AS IS", WITHOUT │
│WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, │
│INCLUDING BUT NOT LIMITED TO THE WARRANTIES │
│OF MERCHANTABILITY, FITNESS FOR A │
│PARTICULAR PURPOSE AND NONINFRINGEMENT. IN │
│NO EVENT SHALL THE AUTHORS OR COPYRIGHT │
│HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR │
│OTHER LIABILITY, WHETHER IN AN ACTION OF │
│CONTRACT, TORT OR OTHERWISE, ARISING FROM, │
│OUT OF OR IN CONNECTION WITH THE SOFTWARE │
│OR THE USE OR OTHER DEALINGS IN THE │
│SOFTWARE. │
└────────────────────────────────────────────┘
}}
Comments
Scratch that. The ActivityBoard appears to use a SPI ADC chip rather than an I2C ADC chip.
You'll need to change the ADC section of the program to use AB's SPI chip.
not trying to reinvent the wheel, what i was originally going to do was use a mic => op amp => ADC, but I was just curious how well the adc did on the activity board from a mic input. the numbers i'm getting from a sigma-delta design is about -40 to +240, (and then I was going to send it thru the adc on the board)
the circuit I used was:
regards
Jeff