serial communication - WEIRD
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Hi all, i'm pulling my hair for i do not have a scope...so here it
goes:
I have a BS2OEM connected thru a straight-thru to win2k running ver
1.3 of parallax's terrible editor.
The BS2 is conected to a caller id chip on pins 15, 14 and 13.
Pin 15 should be normally HIGH, 14 LOW and 13 is the data in pin.
Now when a ring arrives Pin15 should go LOW and 14 should go High and
back to Low. (i use these as "interrupts" - without them you should
not be able to read pin13...no valid ring for example)
The values on the pins are ok and everything goes as specified in the
CID datasheet HOWEVER
WITH the serial cable attached (for debug purposes) nothing works.
PIN 15 is LOW and stays LOW after the ring, and pin14 does the same.
Does anybody have an ideea?....
I'm frustrated to the point where i'm going to abandon Parallax for
good and do it the old fashioned way, ASM......Parallax's INCOMPETENT
Technical support engineers say the usual: Send it in for
testing...but TIME IS MONEY
Thanks in advance to anyone who can help outR
Radu
goes:
I have a BS2OEM connected thru a straight-thru to win2k running ver
1.3 of parallax's terrible editor.
The BS2 is conected to a caller id chip on pins 15, 14 and 13.
Pin 15 should be normally HIGH, 14 LOW and 13 is the data in pin.
Now when a ring arrives Pin15 should go LOW and 14 should go High and
back to Low. (i use these as "interrupts" - without them you should
not be able to read pin13...no valid ring for example)
The values on the pins are ok and everything goes as specified in the
CID datasheet HOWEVER
WITH the serial cable attached (for debug purposes) nothing works.
PIN 15 is LOW and stays LOW after the ring, and pin14 does the same.
Does anybody have an ideea?....
I'm frustrated to the point where i'm going to abandon Parallax for
good and do it the old fashioned way, ASM......Parallax's INCOMPETENT
Technical support engineers say the usual: Send it in for
testing...but TIME IS MONEY
Thanks in advance to anyone who can help outR
Radu
Comments
> The BS2 is conected to a caller id chip on pins 15, 14 and 13.
> Pin 15 should be normally HIGH, 14 LOW and 13 is the data in pin.
Are 13, 14, & 15 being used as inputs, or is 15 an in, 14 an out, and 13 for
data?
> Now when a ring arrives Pin15 should go LOW and 14 should go High and
> back to Low.
Then, a ring causes the CID to pull pin 15 low and toggle pin 14 high then
back to low?
Or is pin 14 an output that pulses high to tell the CID to transmit?
(i use these as "interrupts" - without them you should
> not be able to read pin13...no valid ring for example)
Does the CID send data to pin 13 then??
> The values on the pins are ok and everything goes as specified in the
> CID datasheet HOWEVER
> WITH the serial cable attached (for debug purposes) nothing works.
> PIN 15 is LOW and stays LOW after the ring, and pin14 does the same.
> Does anybody have an ideea?....
Describe the CID device and your I/O a ltlle more clearly, then some ideasm
ay pop up.
Have you tried this with a different cable? different Stamp, etc?
Chris
I salute your patient response. We could all benefit from your thoughtful
example. In this kind of "tell it like it is" forum, it is easy to fire off
a caustic response or take a cheap shot at someone to a post that was
written in a moment of frustration. Taking your valuable time to bring
someone back down and calmly walk them through their problem is admirable
and should be recognized. While I'm on my soapbox, let me thank all the
mentors in this group who, daily, take the time to help their fellow stampers.
Mike
At 02:43 PM 3/14/2002 -0500, you wrote:
>Please take a deep breath, and help me understand what you mean.
_________________________________
Mike Walsh
walsh@i...
[noparse][[/noparse]Non-text portions of this message have been removed]
Yes it must have been a moment of frustration...here is a more
detailed explanation of the problem.
I am using pins 15 (RDET), 14 (CDET) and 13 (DATA) as inputs from the
CID chip.
Here is a crude waveform of what should happen (and does happen with
the cable off)
RING
<1ST
<2ND
____ ______
RDET |_________| |___ <-- connected with 22k pullup
_________ __ <---22k pullup
CDET _____| |____|
DATA
||||||||||||||----
1) when RDET goes low we have a valid ring (data will be sent ONLY if
this happens)
2) When CDET goes low after a period of high we have a valid carrier
(again ONLY if this happens)
3) Data is sent serially with true polarity...so there is no need for
pullup.
My problem:
When re-connecting the serial cable (after I programmed it with DEBUG
statements, then unpluged the cable and reset) the following happens:
1) RDET is somwhere at 0.20 V and when the phone rings goes to 0.00
(SMALL CHANGE and RDET is
not High to begin with)
2) CDET is deffinetly 0.0 V and remains there despite the ring
Situation:
I can not debug anything...because i cant connect my normal serial
cable (which works fine when programming) to my stamp for it causes
an error in the circuit and thus renders it unsusable