[U-Boot-Users] U-Boot problems with MPC8272ADS

[U-Boot-Users] U-Boot problems with MPC8272ADS

[Manil Gaouar]

Hi there,

 

I installed u-boot on my mpc8272ads board, and when I connect the board
with a serial link to my pc, I don't see any output in the console, I
use cu S0 at 115200, I have connected a JTAG to see what's happening in the
board I can see that the PC register is changing and going through the
memory, and the pc will be stuck in an infinite loop which means that he
is waiting for an input, probable the command prompt. I have compared
different positions in my PC register and the u-boot.map and I can see
which function my code is at, so u-boot is running, but why I don't have
a display??

 

Any help will be much appreciated.

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[U-Boot-Users] U-Boot problems with MPC8272ADS

[Scott Wood]

Manil Gaouar wrote:
> I installed u-boot on my mpc8272ads board, and when I connect the
> board with a serial link to my pc, I don?t see any output in the
> console, I use cu S0 at 115200, I have connected a JTAG to see what?s
> happening in the board I can see that the PC register is changing and
> going through the memory, and the pc will be stuck in an infinite
> loop which means that he is waiting for an input,

That's hardly the only case in which code can get stuck in an infinite loop.

> probable the command prompt. I have compared different positions in
> my PC register and the u-boot.map and I can see which function my
> code is at, so u-boot is running, but why I don?t have a display??

Did you check that the serial port is properly initialized, including 
I/O pin and BRG setup?  Can you get serial output by manually poking the 
registers with the BDI?

-Scott

[U-Boot-Users] U-Boot problems with MPC8272ADS

[Jerry Van Baren]

Scott Wood wrote:
> Manil Gaouar wrote:
>> I installed u-boot on my mpc8272ads board, and when I connect the
>> board with a serial link to my pc, I don?t see any output in the
>> console, I use cu S0 at 115200, I have connected a JTAG to see what?s
>> happening in the board I can see that the PC register is changing and
>> going through the memory, and the pc will be stuck in an infinite
>> loop which means that he is waiting for an input,
> 
> That's hardly the only case in which code can get stuck in an infinite loop.

When you halt the CPU with the JTAG, what the PC value?  Look it up in 
your u-boot link map, where is it looping?

>> probable the command prompt. I have compared different positions in
>> my PC register and the u-boot.map and I can see which function my
>> code is at, so u-boot is running, but why I don?t have a display??
> 
> Did you check that the serial port is properly initialized, including 
> I/O pin and BRG setup?  Can you get serial output by manually poking the 
> registers with the BDI?
> 
> -Scott

The second dumbest question: did you plug your serial cable into _both_ 
of the mpc8272ads board's serial ports?

The third dumbest question: did you try different baud rates on your PC 
(or, better, look at the board's serial output with an o'scope)?

gvb
P.S. The first dumbest question is "Is it plugged in?"

[U-Boot-Users] U-Boot problems with MPC8272ADS

[Manil Gaouar]

When I halt the CPU in the infinite loop I can see that my PC is at
0x03fe88b0, if I subtract 0x3fc5000 = 0x000238b4 in flash =
0xfff238b4...according to u-boot.map this is the function serial_getc()
which seems that u-boot is running and waiting for an input, and I still
don't have any display on my console.

I have tried both serial ports with no results. I changed the baud rate
also.

Scott: How can you write something in the serial port with the BDI it
looks like you have to set many registers before sending one byte
through the serial cable?

I will investigate more and let you know, I am glad that u-boot is
running!


Scott Wood wrote:
> Manil Gaouar wrote:
>> I installed u-boot on my mpc8272ads board, and when I connect the
>> board with a serial link to my pc, I don't see any output in the
>> console, I use cu S0 at 115200, I have connected a JTAG to see what's
>> happening in the board I can see that the PC register is changing and
>> going through the memory, and the pc will be stuck in an infinite
>> loop which means that he is waiting for an input,
> 
> That's hardly the only case in which code can get stuck in an infinite
loop.

When you halt the CPU with the JTAG, what the PC value?  Look it up in 
your u-boot link map, where is it looping?

>> probable the command prompt. I have compared different positions in
>> my PC register and the u-boot.map and I can see which function my
>> code is at, so u-boot is running, but why I don't have a display??
> 
> Did you check that the serial port is properly initialized, including 
> I/O pin and BRG setup?  Can you get serial output by manually poking
the 
> registers with the BDI?
> 
> -Scott

The second dumbest question: did you plug your serial cable into _both_ 
of the mpc8272ads board's serial ports?

The third dumbest question: did you try different baud rates on your PC 
(or, better, look at the board's serial output with an o'scope)?

gvb
P.S. The first dumbest question is "Is it plugged in?"

[U-Boot-Users] U-Boot problems with MPC8272ADS

[Ben Warren]

Manil Gaouar wrote:
> When I halt the CPU in the infinite loop I can see that my PC is at
> 0x03fe88b0, if I subtract 0x3fc5000 = 0x000238b4 in flash =
> 0xfff238b4...according to u-boot.map this is the function serial_getc()
> which seems that u-boot is running and waiting for an input, and I still
> don't have any display on my console.
>
> I have tried both serial ports with no results. I changed the baud rate
> also.
>
> Scott: How can you write something in the serial port with the BDI it
> looks like you have to set many registers before sending one byte
> through the serial cable?
>
> I will investigate more and let you know, I am glad that u-boot is
> running!
>
>   
Jerry suggested you look at the TD/RD signals on an oscilloscope. Have 
you done this yet? Much of my life has been wasted tracing this type of 
stuff to incorrect terminal settings, missing null modem adaptor etc., 
and the o-scope can be very revealing. I don't think I'm alone here...

regards,
Ben

[U-Boot-Users] U-Boot problems with MPC8272ADS

[Manil Gaouar]

Finally it worked!

My serial cable was crossed!!!! Go figure why!

With a direct flat serial everything worked fine...thx for the help...

Manil Gaouar wrote:
> When I halt the CPU in the infinite loop I can see that my PC is at
> 0x03fe88b0, if I subtract 0x3fc5000 = 0x000238b4 in flash =
> 0xfff238b4...according to u-boot.map this is the function
serial_getc()
> which seems that u-boot is running and waiting for an input, and I
still
> don't have any display on my console.
>
> I have tried both serial ports with no results. I changed the baud
rate
> also.
>
> Scott: How can you write something in the serial port with the BDI it
> looks like you have to set many registers before sending one byte
> through the serial cable?
>
> I will investigate more and let you know, I am glad that u-boot is
> running!
>
>   
Jerry suggested you look at the TD/RD signals on an oscilloscope. Have 
you done this yet? Much of my life has been wasted tracing this type of 
stuff to incorrect terminal settings, missing null modem adaptor etc., 
and the o-scope can be very revealing. I don't think I'm alone here...

regards,
Ben

[U-Boot-Users] U-Boot problems with MPC8272ADS

[Ben Warren]

Manil Gaouar wrote:
> Finally it worked!
>
> My serial cable was crossed!!!! Go figure why!
>
> With a direct flat serial everything worked fine...thx for the help...
>   
Fantastic! Welcome to the "I've been kicked in the butt by RS-232" club.

regards,
Ben