Re: Help in accessing GPIOs in an i.MX21 (ADS21 board)

I'm out of ideas. If you've given us the correct unmanaged code declaration
and if the managed code declaration you've posted here, modified to return
byte, not Int16, is what you're using, it should work.

HOLD ON. In your description, you called DDKGetGpioSignalState a "method".
It's *not* a method of a C++ class, is it?

Paul T.

"Mario" <alphatommy@xxxxxxxxxxx> wrote in message
news:1158883525.494897.272670@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi Paul,

If you mean that mx21ddk.dll contains method DDKGetGpioSignalState, the
answer is yes. GPIOHANDLE is declared in the unmanaged code as typedef
void* GPIOHANDLE. It should be the same size as IntPtr because handles
to other peripherals(PWM, I2C, and SPI) are declared in a similar way
and I was successful in accessing them from my managed code using
IntPtr.


-- mario


Paul G. Tobey [eMVP] wrote:
As far as I know, there's no layer between your managed code and the DLL
it's calling, but, again, those calls are *not* standard Windows CE
calls.
You are breaking in mx21ddk.dll in the call DDKGetGpioSignalState()? We
should also check, how is GPIOHANDLE declared by the unmanaged code?
It's
not a different size than IntPtr or something, is it?

Paul T.


"Mario" <alphatommy@xxxxxxxxxxx> wrote in message
news:1158880364.964997.312830@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi Paul,

The size of enumeration is 32-bits. I built a simple unmanaged
application and used sizeof on the enumration and it returned a value
of 4. By declaring the parameters to be Int32 and passing values of
0x000002 or 0x000003, I still see at the driver side that it sees
Port_A, which is 0x00000000. Is there a layer between my managed
application and the driver that I can snoop and see what actually was
passed? Thanks all for all your responses.

mario


Paul G. Tobey [eMVP] wrote:
OK, so forget about trying to P/Invoke with a managed enumeration.
Declare
the parameter as an Int32 and pass the value that corresponds to some
other
port (1, 2, 3, whatever), and see what you get in that case. It would
be
useful to verify the size of the enumeration expected by the unmanaged
code,
also. I would expect it to be 32-bit, but I could be wrong about
that.

Paul T.

"Mario" <alphatommy@xxxxxxxxxxx> wrote in message
news:1158870731.936903.11560@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi Paul,

Sorry, what I meant by "did not work" was that regardless of what
value
I sent as Port (GPIO_PORT_B, C, D, E or MAX) I still see that the
value
passed for Port is GPIO_PORT_A. I see this by breaking on the
driver,
and GPIO_PORT_A is the value that shows up when I place the cursor
on
top of Port or through Quick Watch. The value that is returned is
wrong because it is looking at the different port that I have
selected.
I still have to try to call the method from an umanaged application.
Thanks.

-- mario

Paul G. Tobey [eMVP] wrote:
Sorry, "did not work" is useless information. What value did you
pass?
What was returned in the byte? What do you get when you pass the
same
values from unmanaged code?

Paul T.

"Mario" <alphatommy@xxxxxxxxxxx> wrote in message
news:1158794169.432339.250470@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi Paul,

I could try using byte for return value. On the GPIO_PORT, I
have
tried Int32 before, but it did not work. Thanks.

-- mario


Paul G. Tobey [eMVP] wrote:
Well, that return type is wrong. Clearly you should be
returning
some
8-bit
value, which you aren't. Try 'byte'; it's a good choice.

Try also, for now, just making the GPIO_PORT parameter an Int32
and
passing
the right value as an integer to it. Does that work?

Paul T.


"Mario" <alphatommy@xxxxxxxxxxx> wrote in message
news:1158791251.466377.92460@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi Paul,

For the method INT8 DDKGetGpioSignalState(GPIOHANDLE
gpiohandle,
GPIO_PORT port, UINT32 signal)

I did the following:

[DllImport ("mx21ddk.dll")] //mx21ddk.dll contains the
methods
that
I am calling
public static extern Int16 DDKGetGpioSignalState(IntPtr
gpiohandle,
GPIO_PORT port, UInt32 signal);

The reason why I used Int16 is because there is no Int16 in
C#.

//GPIO in C#
public enum
{
GPIO_PORT_A,
GPIO_PORT_B,
GPIO_PORT_C,
GPIO_PORT_D,
GPIO_PORT_E,
GPIO_PORT_F,
GPIOPORTMAX
}

Please let me know if you see any errors. Thanks.

mario


Paul G. Tobey [eMVP] wrote:
Those don't appear to be standard DDK calls to me, but I'm no
expert
on
any
i.MX21 BSPs. How have you P/Invoked them? GPIOHANDLE is
probably
an
IntPtr, GPIO_PORT you can probably create an enum for that
corresponds
directly to what the C/C++ code uses, UINT32 is pretty
obvious,
'uint',
etc.
What value, integer value, are you passing in the GPIO_PORT
parameters?

Paul T.

"Mario" <alphatommy@xxxxxxxxxxx> wrote in message
news:1158785258.148715.111740@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi Paul,

I have tried the following methods (their signatures are as
follow):

1. INT8 DDKGetGpioSignalState(GPIOHANDLE gpiohandle,
GPIO_PORT
port,
UINT32 signal)
2. void DDKSetGpioSignalState(GPIOHANDLE gpiohandle,
GPIO_PORT
port,
UINT32 signal, UINT8 state, BOOL bInPowerMode)

3. UINT32 DDKGetGpioSignals(GPIOHANDLE gpiohandle,
GPIO_PORT
port,
UINT32 signalMask)

4. void DDKSetGpioSignals(GPIOHANDLE gpiohandle,
GPIO_PORT
port,
UINT32 signalMask, UINT32 stateMask)

GPIO_PORT is defined in the driver header as:

typedef enum {
GPIO_PORT_A,
GPIO_PORT_B,
GPIO_PORT_C,
GPIO_PORT_D,
GPIO_PORT_E,
GPIO_PORT_F,
GPIO_PORT_MAX,
} GPIO_PORT;

Thanks in advance for any input.

-- mario


Paul G. Tobey [eMVP] wrote:
What GPIO method calls?

Paul T.

"Mario" <alphatommy@xxxxxxxxxxx> wrote in message
news:1158076582.805617.137440@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi,

Has anyone had any success in accessing (reading and
writing)
the
GPIOs
in a Freescale i.MX21 (ADS21 board) from a managed code
application?
The problem that I have is that regardless of which port
parameter I
pass in the GPIO method calls, the GPIO driver always
take
Port_A
as
default. The rest of the parameters are passed
correctly.
Any
inputs
or suggestions on how to fix this is appreciated.
Thanks.

I am not sure if this is the correct forum, but I did
not
get
any
response after posting the same question in the
freescale
site
for
almost two weeks.


-- mario









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