Dear fiends
Hi
I've written a code in order to use GPIO pins as output ports. my code is
correct and works properly, but when i connect GPIO pins to another device pins,
DSP starts up abnormally and code composer cannot load the .out file. By the
way, I noticed that when code composer checks target endianness, it finds a
mismatching problem between my DSP and my built code. However, i can run my code
on DSK in little endianness mode(default mode) and without any external pin
connection. As another thing, when i connect GPIO pins to other device, LED_1
turns off! I would be so grateful if anyone can help me through this.
Kind regards
Babak
_____________________________________
GPIO board connections
Started by ●February 2, 2010
Reply by ●February 2, 20102010-02-02
Babak-
> I've written a code in order to use GPIO pins as output ports.
> my code is correct and works properly, but when i
> connect GPIO pins to another device pins, DSP starts up
> abnormally and code composer cannot load the .out file. By the
> way, I noticed that when code composer checks target endianness,
> it finds a mismatching problem between my DSP and my
> built code. However, i can run my code on DSK in little
> endianness mode(default mode) and without any external pin
> connection. As another thing, when i connect GPIO pins to other
> device, LED_1 turns off! I would be so grateful if
> anyone can help me through this.
My guess is that your GPIO lines share pull-up (or pull-down) Rs with some boot-mode lines, so the external
connections interfere at boot-time.
Did you guys design your own board? My guess is yes, and you shared too many pull-ups/pull-downs, violating the
design rules for keeping GPIO separate.
-Jeff
_____________________________________
> I've written a code in order to use GPIO pins as output ports.
> my code is correct and works properly, but when i
> connect GPIO pins to another device pins, DSP starts up
> abnormally and code composer cannot load the .out file. By the
> way, I noticed that when code composer checks target endianness,
> it finds a mismatching problem between my DSP and my
> built code. However, i can run my code on DSK in little
> endianness mode(default mode) and without any external pin
> connection. As another thing, when i connect GPIO pins to other
> device, LED_1 turns off! I would be so grateful if
> anyone can help me through this.
My guess is that your GPIO lines share pull-up (or pull-down) Rs with some boot-mode lines, so the external
connections interfere at boot-time.
Did you guys design your own board? My guess is yes, and you shared too many pull-ups/pull-downs, violating the
design rules for keeping GPIO separate.
-Jeff
_____________________________________
Reply by ●February 2, 20102010-02-02
babak,
there are certain GPIO pins that are used during the boot process to determine the boot mode of the DSP.
It sounds like the load from the other device is driving those pins to an 'invalid' state.
regarding LED-1.
(I'm not sure what LED-1 indicates)
if LED-1 indicates power, then the other device is placing a very heavy load on the power supply for the DSP. In this case, I would suggest changing the connections to the other device to use opto isolators or something similar.
You might also re-examine the connections to the other device to re-assure that the connections are to GPIO pins and not to a power rail.
Generally, the GPIO pins that are used to determine the boot mode of the DSP must not have any other load on them until after the /reset signal has been removed for some period of time.
However, I suspect the power is being drawn way down by the other device.
You might try disconnecting from the other device, then only connecting/adding one new signal at a time, probably starting with the common ground signals.
After each new connection to the other device, re-boot to assure proper boot sequence has not been disturbed.
R. Williams
---------- Original Message -----------
From: b...@yahoo.com
To: c...
Sent: Tue, 02 Feb 2010 12:21:41 -0500
Subject: [c6x] GPIO board connections
>
>
> Dear fiends
>
> Hi
> I've written a code in order to use GPIO pins as output ports. my code is correct and works properly, but when i connect GPIO pins to another device pins, DSP starts up abnormally and code composer cannot load the .out file. By the way, I noticed that when code composer checks target endianness, it finds a mismatching problem between my DSP and my built code. However, i can run my code on DSK in little endianness mode(default mode) and without any external pin connection. As another thing, when i connect GPIO pins to other device, LED_1 turns off! I would be so grateful if anyone can help me through this.
>
> Kind regards
> Babak
------- End of Original Message -------
there are certain GPIO pins that are used during the boot process to determine the boot mode of the DSP.
It sounds like the load from the other device is driving those pins to an 'invalid' state.
regarding LED-1.
(I'm not sure what LED-1 indicates)
if LED-1 indicates power, then the other device is placing a very heavy load on the power supply for the DSP. In this case, I would suggest changing the connections to the other device to use opto isolators or something similar.
You might also re-examine the connections to the other device to re-assure that the connections are to GPIO pins and not to a power rail.
Generally, the GPIO pins that are used to determine the boot mode of the DSP must not have any other load on them until after the /reset signal has been removed for some period of time.
However, I suspect the power is being drawn way down by the other device.
You might try disconnecting from the other device, then only connecting/adding one new signal at a time, probably starting with the common ground signals.
After each new connection to the other device, re-boot to assure proper boot sequence has not been disturbed.
R. Williams
---------- Original Message -----------
From: b...@yahoo.com
To: c...
Sent: Tue, 02 Feb 2010 12:21:41 -0500
Subject: [c6x] GPIO board connections
>
>
> Dear fiends
>
> Hi
> I've written a code in order to use GPIO pins as output ports. my code is correct and works properly, but when i connect GPIO pins to another device pins, DSP starts up abnormally and code composer cannot load the .out file. By the way, I noticed that when code composer checks target endianness, it finds a mismatching problem between my DSP and my built code. However, i can run my code on DSK in little endianness mode(default mode) and without any external pin connection. As another thing, when i connect GPIO pins to other device, LED_1 turns off! I would be so grateful if anyone can help me through this.
>
> Kind regards
> Babak
------- End of Original Message -------
