I2C

Archiver · 2000-05-18 15:36

Found some BSI and BSII I2C code at www.hth.com (page is Swedish).

Archiver · 2000-08-29 22:50

hello,

has anyone experience with the pcf8573, pcf8574, pcf8583,pcf8584 or saa1064?
Want to connect them to a basicstamp, haven'figured out how yet!

thanks pieter-jan
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Archiver · 2000-10-03 14:38

hello all,

can't get my code working with i2c, hte basics of the code are good, because
when i test it with a 24c65 it works fine.

can anybody take a look into it, is this code to fast for the i2c protocol?

anyway, it's different from peter anderson code of the i2c, think it does
the same...

all info is welcome, i'm a littlebit desperate [noparse];)[/noparse]

'i2c subroutines
'pcf8583

'VARIABELEN
i2data var byte
i2datahi var i2data.highnib
i2datalo var i2data.lownib
i2dt con 0
i2clk con 1
i2ack var bit
i2memwr con %10100000
i2memrd con %10100001
temp1 var byte
temp1hi var temp1.highnib
temp1lo var temp1.lownib
temp2 var nib
memtop con 150
i var word

TEST:
'just a read test, i'm not writing yet
for i=1 to 50000
gosub lees2
pause 100
next
end

lees2:
gosub i2start
i2data = %10100000
gosub i2tx
gosub ackrx
i2data = %00000000
gosub i2tx
gosub ackrx
gosub i2start
i2data = %10100001
gosub i2tx
gosub ackrx
'this is the hard way,
'according to me a start and direct
'10100001 must do the trick also
'get strange values with this program
gosub i2rx
temp1 =i2data
gosub acktx
debug "A",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "B",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "C",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "D",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "E", dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "F",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "G",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
' gosub acktx
debug "H", dec3 ? temp1,cr
gosub i2stop
return

I2START:
high i2dt
high i2clk
low i2dt
return

I2STOP:
low i2dt
high i2clk
high i2dt
return

I2TX:
'transmit data
shiftout i2dt,i2clk,1,[noparse][[/noparse]i2data]
return

I2RX:
shiftin i2dt,i2clk,0,[noparse][[/noparse]i2data]
return

ACKTX:
shiftout i2dt,i2clk,1,[noparse][[/noparse]%0\1]
return

ACKRX:
shiftin i2dt,i2clk,0,[noparse][[/noparse]i2ack\1]
if i2ack=0 then ret
debug "ack failed"
debug hex ?i2data
nap 7
return

RET:
return

thanks from pieter-jan!!
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Archiver · 2000-10-03 19:46

hello all,

Can anyone please look at this code, according to me it must work, with a
littlebit of adjustments it works fine with the 24c65 eeprom. Right now i
think i work according specs of the i2c, but quiet different of peter
anderson's code.

Any help is appreciated!!

the chip i'm using has 8 registers that i want to read, it seems two
readings work fine, rest looks like garbage. with a different start address
that two looks fine, rest looks garbage etcetera

many thanks pieter-jan

here is the code...

'i2c subroutines
'pcf8583

'VARIABELEN
i2data var byte
i2datahi var i2data.highnib
i2datalo var i2data.lownib
i2dt con 0
i2clk con 1
i2ack var bit
i2memwr con %10100000
i2memrd con %10100001
temp1 var byte
temp1hi var temp1.highnib
temp1lo var temp1.lownib
temp2 var nib
memtop con 150
i var word

TEST:
for i=1 to 50000
gosub lees2
pause 100
next
end

lees2:
gosub i2start
i2data = %10100000
gosub i2tx
gosub ackrx
i2data = %00000000
gosub i2tx
gosub ackrx
gosub i2start
i2data = %10100001
gosub i2tx
gosub ackrx
'this is the hard way,
'according to me a start and direct
'10100001 must do the trick also
'get strange values with this program
gosub i2rx
temp1 =i2data
gosub acktx
debug "A",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "B",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "C",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "D",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "E", dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "F",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
debug "G",dec3 ? temp1,cr
gosub i2rx
temp1 =i2data
' gosub acktx
debug "H", dec3 ? temp1,cr
gosub i2stop
return

I2START:
high i2dt
high i2clk
low i2dt
return

I2STOP:
low i2dt
high i2clk
high i2dt
return

I2TX:
'transmit data
shiftout i2dt,i2clk,1,[noparse][[/noparse]i2data]
return

I2RX:
shiftin i2dt,i2clk,0,[noparse][[/noparse]i2data]
return

ACKTX:
shiftout i2dt,i2clk,1,[noparse][[/noparse]%0\1]
return

ACKRX:
shiftin i2dt,i2clk,0,[noparse][[/noparse]i2ack\1]
if i2ack=0 then ret
debug "ack failed"
debug hex ?i2data
nap 7
return

RET:
return

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Archiver · 2000-10-04 02:53

Note that the two states for the I2C should be a hard zero (GRD) and
high impedance which I accomplish by making the pin an input. The
high impedance permits the slave to pull the bus low.

But, if this code is partially working for you, the problem may be in
failing to ACK after the receipt of the each byte. I have entered
these in CAPS below.

Note that a NACK is sent prior to the STOP to inicate to the slave,
there is no more.

Peter H. Anderson, http://www.phanderson.com/stamp
Homebrew BS2

> gosub i2rx
> temp1 =i2data
> gosub acktx
> debug "A",dec3 ? temp1,cr
> gosub i2rx
> temp1 =i2data
GOSUB ACKTX
> debug "B",dec3 ? temp1,cr
> gosub i2rx
> temp1 =i2data
GOSUB ACKTX
> debug "C",dec3 ? temp1,cr
> gosub i2rx
> temp1 =i2data
GOSUB ACKTX
> debug "D",dec3 ? temp1,cr
> gosub i2rx
> temp1 =i2data
GOSUB ACKTX
> debug "E", dec3 ? temp1,cr
> gosub i2rx
> temp1 =i2data
GOSUB ACKTX
> debug "F",dec3 ? temp1,cr
> gosub i2rx
> temp1 =i2data
GOSUB ACKTX
> debug "G",dec3 ? temp1,cr
> gosub i2rx
> temp1 =i2data
GOSUB ACKRX
> debug "H", dec3 ? temp1,cr
> gosub i2stop
> return
>
>
> I2START:
> high i2dt
> high i2clk
> low i2dt
> return
>
> I2STOP:
> low i2dt
> high i2clk
> high i2dt
> return
>
> I2TX:
> 'transmit data
> shiftout i2dt,i2clk,1,[noparse][[/noparse]i2data]
> return
>
> I2RX:
> shiftin i2dt,i2clk,0,[noparse][[/noparse]i2data]
> return
>
> ACKTX:
> shiftout i2dt,i2clk,1,[noparse][[/noparse]%0\1]
> return
>
> ACKRX:
> shiftin i2dt,i2clk,0,[noparse][[/noparse]i2ack\1]
> if i2ack=0 then ret
> debug "ack failed"
> debug hex ?i2data
> nap 7
> return
>
>
> RET:
> return

Archiver · 2000-10-04 12:44

hello all,

I'm not sure that i use the high speed bus, it's not named at the datasheet
(as far as i know)

The bs2 is the master, so i am using single master.

if i have to extend the clock low, then shiftout isn't working anymore?
(shiftout has a timing i can't program?) and i should use peter andersons
code...

thanks

pieter-jan

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Archiver · 2001-05-08 20:27

hello,

has anyone ever written a program to read/write data to/from a chipcard
(e.g. bank account card) via the I2C-Bus provided by the Stamp IIP? I know i
cannot write money on it :-) but I know that you still can read and write
on them...

Thanx for help,

uli

www.raumschiff-interactive.de

Archiver · 2004-05-19 06:14

Does anyone know how far a stamp2 can be from an I2C peripheral unit?

Michael

Archiver · 2004-05-19 10:51

In a message dated 5/19/2004 1:45:29 AM Eastern Daylight Time,
magzi@p... writes:

> Does anyone know how far a stamp2 can be from an I2C peripheral unit?
>

Do you mean how far and still work?

Sid

[noparse][[/noparse]Non-text portions of this message have been removed]

Archiver · 2004-05-19 17:03

In a message dated 5/19/2004 3:40:54 PM Eastern Daylight Time,
magzi@p... writes:

> yes that's what I mean
>
>

I have run peripherals 40 feet on 22 gauge wire. My guess is that you could
probably go 100 feet with 20 gauge. Stranded would be better than solid.

Sid

[noparse][[/noparse]Non-text portions of this message have been removed]

Archiver · 2004-05-19 20:35

--- In basicstamps@yahoogroups.com, Newzed@a... wrote:
> In a message dated 5/19/2004 1:45:29 AM Eastern Daylight Time,
> magzi@p... writes:
>
>
> > Does anyone know how far a stamp2 can be from an I2C peripheral unit?
> >
>
> Do you mean how far and still work?
>
> Sid

yes that's what I mean

Archiver · 2004-05-20 03:51

I think it depends mostly on what pullup resistor values you use. Short runs
(same PCB) use a 10k, longer runs use 4.7k, really long runs could use
lower. You need supply a minimum amount of current (check datasheet) and the
wire resistance adds to the pullup resistance, possible making the current
to low to be read correctly.

Of course RFI becomes a problem with longer runs - may need shielded cable
etc.

>

Original Message

> From: Newzed@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=lyZLxYUML688fOw80zzrHNdKfAcuyYuZOBTwvFtFfzz58TuwM_LupwcrTtTmRLxsR2FMhMywAg]Newzed@a...[/url
> Sent: May 19, 2004 1:03 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] Re: i2c
>
>
> In a message dated 5/19/2004 3:40:54 PM Eastern Daylight Time,
> magzi@p... writes:
>
>
> > yes that's what I mean
> >
> >
>
> I have run peripherals 40 feet on 22 gauge wire. My guess is
> that you could
> probably go 100 feet with 20 gauge. Stranded would be better than solid.
>
> Sid
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
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I2C

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