[U-Boot-Users] 8260 SMC2 driver not receiving characters

Wolfgang Denk wd at denx.de
Tue Jun 10 00:05:59 CEST 2003

Dear Kodis,

in message < at jittlov.qualcomm.com> you wrote:
>    I made a u-boot binary with the custom configuration for my 8260 
> board.  I am using SMC2 as the serial device. When I boot using BDI, It 
> comes upto the boot prompt and does not receive characters.  When I don't 

Can you see the characters on the wire? (Check with an oscilloscope).

> use BDI, it does not even come to the command prompt, it crashes in 
> between, I don't know why?.  I am guessing that the serial driver reception 

Probably your port of U-Boot is broken.

> is broken?.  I was looking at the serial driver code, looks like it is 
> using polling mechanism instead of interrupts.  Is the problem points to 

This is correct. U-Boot uses polling drivers.

> the serial clks or the driver itself?  Has anyone used SMC2 as the serial 
> driver in the U-boot code.  I was comparing the getc function of 
> smc_serial.c and uart.c, one is using the while loop to wait and the other 
> is using the for loop to wait, does it make a difference.  Can anyone tell 
> me what is going on?

We used SMC1 and S<C2 on quite a lot of boards. No problems ever.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
What is research but a blind date with knowledge?      -- Will Harvey

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