DP83826E: how to drive LED1

Dominik M.

Part Number: DP83826E
Other Parts Discussed in Thread: DP83826I

Hi Team,
I'm using a DP83826E in Basic Mode and try to control a LED (strapped via resistor to GND, which means active high output is necessary to drive
the LED) connected to LED1 /PIN 31 manually via software. I set therefore:

- LED1_GPIO_CFG Register (304h) bit 2-0 to 0h (LED1)

- LEDCFG2 Register (469h), bit 2 to 1h (active high), bit 1 to 1h (high) and bit 0 to 0h (drive LED polarity).

But Pin 31 stays always low - is there anything else to configure which i forgot?

I think that there are some mistakes in the documentation DP83826i, (revised October 2020) which are related to the LED1 Output:
- page 46, Figure 9-9, upper, right block: Pin31/Pin28/Pin29: Register-Addresses are always 0x303, but should be 0x304/0x305/0x306 in my opinion
- page 80, Table 9-19, Bit 5-3, Description: should be cfg_led1_gpio_ctrl[2:0] instead of cfg_led0_gpio_ctrl[2:0] in my opinion
- page 80, Table 9-19, Bit 2-0, Type: should be R/W instead of R in my opinion
- page 86, Table 9-94, Bit 15-12, Type: should be R/W instead of R in my opinion

Thanks a lot in advance and with best regards
Dominik

over 4 years ago

0 Lucas Wolter over 4 years ago

TI__Mastermind 29770 points

Hi Dominik,

Try writing 1 to bit 0 of register 0x469. I believe writing 1 is for normal operation while writing 0 is to drive LED polarity.

I see these errors in the datasheet. They will be corrected in the next revision.

Thanks,

Lucas

All information in this correspondence and in any related correspondence is provided “as is” and “with all faults”, and it is subject to TI’s Important Notice (http://www.ti.com/corp/docs/legal/important-notice.shtml).

0 Dominik M. over 4 years ago in reply to Lucas Wolter

Prodigy 10 points

Hi Lucas,

thanks a lot for your fast response.

Unfortunately, this didn't solve the problem. I've even tried all possible combinations of the 3 lowest bits of register 0x469 - the output never goes to high. Is there any other register which has to be set to be able to drive the LED1 output manually via register 0x469?

Best regards,

Dominik

+1 Lucas Wolter over 4 years ago in reply to Dominik M.

TI__Mastermind 29770 points

Hi Dominik,

Are you aware of the procedure needed to read/write extended registers? 0x304 and 0x469 are both extended registers and cannot be written to directly.

Thanks,

Lucas

0 Dominik M. over 4 years ago in reply to Lucas Wolter

Prodigy 10 points

Hi Lucas,

thank you for this hint! Indeed, I overlooked that.

Now it works with setting 0x0304, bit 2-0 to 0 and setting 0x0469, bit 2 (polarity) to 1 and bit 0 (drive enable) to 1 and controlling the LED - output via bit 1.

Thanks a lot for your help!

Dominik

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DP83826E: how to drive LED1