GPIO 129 is not working as expected

Hi, 

In order to have gpio_129 outputted on the device pad you need to set CONTROL_CORE_PAD0_I2C2_SDA_PAD1_I2C3_SCL[2:0]I2C2_SDA_MUXMODE = 0x3 (Select gpio_129).

Regarding Extended-Drain I/O and PBIAS Cell, I think you've got it wrong. This functionality is available only for the pads associated with the MMC/SD/SDIO1 controller, they are not applicable for GPIO_129 (ball D26 of the SoC).

Best Regards,

Yordan

Thanks for the reply Yordan

             I have done the multiplexing in x-loader for

IDIS | PTD | EN | M4

I have checked these values by readin the corresponding 129 pad register.

I read the PBIAS register for values and got 0x8387. 

Its working ok now for the intended purpose. But I have to test more. I'll reply again.

Yordan I just need to know that if gpio 122 is getting 3.0 volt supply , then 129 also have to get same 3 volt supply?

Is this supply is termed as sim_vdds and sdmmc_vdds? 

In my hardware gpio 122, 123 are connected to 3.0 volts pull up resistors, so the gpio 129 have to be connected to 3.0 volts supply.

If this is so, then sim_vdds = 3.0(I read control_pbias_lite register and pbiaslitesupplyhigh1 = 1,so it says that 129 is supplied by 3.0 volts supply) volts and I should not try to make vmode1 = 0 to get 1.8 volts from this gpio as it would be a change from 3.0 volt to 1.8 volts and its a damaging configuration as said by data sheet. 

Is my understanding correct ?

I also am using two boot methods, one is sd boot and other is nand boot. In sd boot I am getting pbias_lite_register as 0x8387 , so my supply is 3.0 volts and stable, but flashing same code in nand gives me 0x101, that says 1.8 volts and not stable. 

I have saw the table 13-67 that says we can only give 1.8 volts to 1.8 volts and 3.0 volts to 3.0 volts. So in programming method 13-24 in the flowchart a condition of 3.0 to 1.8 volts or 1.8 to 3.0 volts if these are damaging or degrading configurations?

Hi,

First of all which Data Manual are you referring to? I am looking at OMAP4460 Data Manual and I can't see Table 13-67 or programming method 13-24.

To answer your question:
"I just need to know that if gpio 122 is getting 3.0 volt supply , then 129 also have to get same 3 volt supply?"

No, in OMAP4460 gpio_122 is muxed on ball AH24 and is supplied by vdds_dv_bank2 and gpio_129 is muxed on ball D26 and is powered by vdds_1p8v. So they are not getting the same power supply.

Moreover, as I see in table Table 3-1. Absolute Maximum Rating Over Junction Temperature Range, supplying 3.0V to your gpios (gpio_122 & gpio_129) is NOT recommended. 

Absolute maximum rating for vdds_dv_bank2  and for vdds_1p8v is 2.10V, and 2.10V is also not recommended to be supplied.

The maximum recommended voltages are: 1.26V or 1.89V for vdds_dv_bank2 (depending if bank2 is in 1.2V or 1.8V mode) & 1.89V for vdds_1p8v.  Working with higher voltages can damage the OMAP pads. 

Best Regards,
Yordan

I am using DM3730 technical reference manual.

OK, I checked DM3730 DM & again gpio_122 & gpio_129 are supplied from different sources:

gpio_122 -> supplied from vdds_mmc1

gpio_129 -> supplied from vdds_x

But in the case of DM3730, you can power those balls with up to 3.6V without damaging the device. Again extended drain I/O configurations are available only for MMC1 ball (where gpio_122 is muxed, not gpio_129).

So you should be able to output 3.0V on your gpios. For more detailed information on DM3730 devices, please post in the corresponding DM37x DaVinci Video Processor Forum: http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/537.aspx

Best Regards,

Yordan