mx28: pull up GPIO pin seems failed

[hwo]

Hi all,

     I come across a problem. I initialize the AUART2.RTS pin(Bank 3, ID 11), and enable it to be a output GPIO pin. At the same time, enable the pull up function. But when I read out the HW_PINCTRL_PULL3  register. I get all 0. The settings in others register like MUX, DOUT, DRIVE and DOE are quite normal.  I haven't modified the pinctrl.c file. It's original.

Why this happens?

{                         

.name  = "AUART2.RTS",   

.id    = PINID_AUART2_RTS,

.fun   = PIN_GPIO,       

.strength      = PAD_4MA,

.voltage       = PAD_3_3V,

.drive         = 1,      

.pullup        = 1,      

.pull          = 1,      

.output        = 1,      

.data          = 0,      

},                        

One more question, does the pull up function affect the GPIO's output? According to the MX28RM, it only disable the gate keeper.

Thanks in advance.

[igorpadykov · Accepted solution]

Hi h k

pull up function does not affect the GPIO's output, however

not all pads have pul-ups, only described in

Table 9-3. i.MX28 Functions with Pullup Resistors  MX28RM

http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM.pdf

Best regards

igor

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