DS90UB928Q-Q1: Ds90ub927 GPIO_Reg7 to DS90ub928 GPIO_Reg7 for Screen Reset function question

Jimmy Huang22

Part Number: DS90UB928Q-Q1

Hi Ti team,

Could you pls help us check below question?

1, if ds90ub927 0x11 to 0x33, ds90ub928 0x21 to 0x55, then GPIO_REG8 can support PWM and Reset transfer, but why GPIO_REG7 can't support Reset function transfer. ( Reset is High or Low voltage)

2, if ds90ub927 0x10 to 0x30, ds90ub928 0x20 to 0x50, then GPIO_REG6 can't support BL_EN function transfer. (BL_EN is High or Low voltage)

So, GPIO_Reg8 can support PWM,Reset and BL_EN function transfer with above reg# set, GPIO_REG6/7 all can't support transfer Reset and BL_EN with above reg# set.

We can only set DS90ub928 GPIO_REG6/7 output High or Low

thanks!

over 6 years ago

0 Charley Cai over 6 years ago

TI__Genius 12866 points

GPIO_REG5, 6, 7, 8 are not designed to send data across the SerDes.

See 927 datasheet 73.13.2, Configuration and state of these pins are not transported from serializer to deserializer as is the case for GPIO[3:0].

GPIO_REG[8:5] are register-only GPIOs and may be programmed as outputs or read as inputs through local register bits only

Best Regards,
Charley Cai

0 Jimmy Huang22 over 6 years ago in reply to Charley Cai

Expert 1470 points

Charley,

Thanks your reply,But we used DS90ub927 to DS90ub926, set above reg#,then GPIO8,GPIO7,GPIO6 all can support PWM,BL-EN and Reset transfer.

I don't know why?

0 Charley Cai over 6 years ago in reply to Jimmy Huang22

TI__Genius 12866 points

Do you have I2S mode enabled?

Best Regards,
Charley Cai

0 Casey McCrea over 6 years ago in reply to Charley Cai

TI__Guru** 103215 points

Jimmy,

Any update on this? Do you still need support on it?

- Casey

0 Jimmy Huang22 over 6 years ago in reply to Casey McCrea

Expert 1470 points

Casey,

Sorry for delay, have let's customer set I2S Model for DS90ub927 to DS90ub928 transfor GPIO8/7/6

DS90ub927 to DS90ub926 set GPIO8/7/6 transfer ok with no set I2S mode enabled

thanks!

0 Casey McCrea over 6 years ago in reply to Jimmy Huang22

TI__Guru** 103215 points

Hello Jimmy,

Not sure I understand - is the problem solved?

Best Regards,

Casey

0 Jimmy Huang22 over 6 years ago in reply to Casey McCrea

Expert 1470 points

Casey,

1, Yes, Set the gpio8/7/6 in I2S mode can transfor the PWM,EN in DS90ub927 to DS90ub928

2, If set GPIO7/6 no in I2S mode, Couldn't transfor PWM,EN in ds90ub927 to DS90ub928

3,If set GPIO7/6 no in I2S mode with DS90ub927 to DS90ub926 can transfor PWM,EN. I don't know why?

0 Charley Cai over 6 years ago in reply to Jimmy Huang22

TI__Genius 12866 points

GPIO7 and 6 are not suppose to be used to transmit signal across the channel when they are in GPIO mode. So the 927, 928 behavior is correct.

It is possible to enable I2S mode and use GPIO 7/6 to send PWM signals. The recommended maximum switching rate when LFMODE=0 (15-85MHz operation) is 100KHz and 50KHz when LFMODE=1 (5-15MHz operation).

Hope this addresses your question.

Best Regards,
Charley Cai

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DS90UB928Q-Q1: Ds90ub927 GPIO_Reg7 to DS90ub928 GPIO_Reg7 for Screen Reset function question