C6747 (OMAP-L137) GPIO access issue

jun yang46050

I am trying to use C6747 GPIO to output data. But it looks no any voltage level change on corresponding GPIO.

I use GPIO0[15:8] for logic output. Following setting procedure was conducted.

1. Go through SYSCFG registers to configure DSP interfaces and setting PINMUX registers as required. For using GPIO0[15:8] as output, PINMUX14 = 0x88111111, and PINMUX15 = 0x11888888. So pins of GPIO0[15:8] are set as GPIO.

2. Set GPIO DIR01 = 0xffff00ff, so GPIO0[15:8] is configured as output.

3. Write data into OUT_DATA01. Suppose voltages on the GPIO0[15:8] pins should change according to the written data.

However, the GPIO0[15:8] didn't change at all. Its levels keeps low, and looks like in 3-state.
Furthermore, CCS shows all GPIO status and data from 0x01e26000 - 0x01e26100 are 0s. Even the Revision ID Register (REVID) of GPIO was 0x00000000, which should be 0x44830105.

Any setting do I missed? Any help or suggestion?

Regards,

Jun

over 14 years ago

0 dabuan over 14 years ago

TI__Genius 14545 points

Jun Yang,

jun yang said:
Any setting do I missed?

In my experience, typically when I see all zero's in the emulator window it means that the module I am trying to communicate with is not powered up. This is a common reason for the emulation registers to stay blank.

The Power and Sleep Controller (PSC) needs to power up the GPIO module as it defaults to an reset state. Please refer to the TMS320C6747 System Reference Guide (PSC section) for detailed steps on how to do so.

0 jun yang46050 over 14 years ago in reply to dabuan

Prodigy 150 points

Drew,

Thanks for your reply. Your analysis is correct. It does need to power on the GPIO module.

Regards,

Jun

0 Mohd Hafiz Fazalul Rahiman over 14 years ago

Prodigy 175 points

Hi,

I want to start learning GPIO on C6747. How do we obtain the related information i.e. PINMUX settings and others? The information in datasheet is very brief. Any other useful sources?

0 Daniel Allred over 14 years ago in reply to Mohd Hafiz Fazalul Rahiman

TI__Genius 17355 points

Please refer to the GPIO user's guide.

The PINMUX settings are documented in the TMS320C6747 System Reference Guide (SYSCFG section)

Regards, Daniel

P.S. - In the future, please start a new thread when you have a question instead of jumping onto the end of a thread that has already been answered. This really helps us to better track what items are open and need to be answered.

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C6747 (OMAP-L137) GPIO access issue