Add-ons

LeMaker 7" LVDS LCD for Banana Pi & Pro

46 12459
It works great!

LeMaker has not had time to write documentation for it yet, but my review has all the info you need to install one.

http://www.mikronauts.com/banana ... -lcd-module-review/
Excellent review, as always!

thank you

Edited by mikronauts at Mon Nov 24, 2014 17:55

Does anyone know the part number for the pfc socket on the Banana Pi?

I was opening it to take the LCD off during some power testing, and the brown part of the connector broke on one end

Turns out the brown part just popped out and did not break!

I'll be updating my review of the 7" display with power consumption figures shortly.

http://www.mikronauts.com/banana ... cd-module-review/4/

Now updated with power usage for:

- boot max
- desktop idle
- after 'sudo halt'

for with/without the 7" LCD

dylan  
Very great

tkaiser  
Edited by tkaiser at Tue Nov 25, 2014 07:47
mikronauts replied at Mon Nov 24, 2014 16:52
Now updated with power usage


Thank you for the update. Two questions remain to me:

- how did you measure consumption exactly (especially between wall and PSU or PSU and Banana Pi)?

- is there a way to 'power off' the display/backlight when it's not needed?

Especially the latter is important since increasing the overall consumption by over 3W 24/7 when the display is only used a small fraction of time seems not the best idea... Would be also ok if there's some sort of a switch on the controller board (otherwise I would go with a LS-7 that uses obviously the same panel, consumes a bit more when active but can be switched off when not in use)

dylan:

thank you!

tkaiser:

You are welcome!

- I measured the power consumption between the PSU and the Banana Pi

- the LCD backlight turned off, however there was still 91mA of current drawn

I think Tony (or someone else from LeMaker) will have to look into why the display is still drawing that much current when the Pi is turned off. It may simply be a driver issue, or perhaps the panel cannot fully be powered down under software control.

Edited by HWL_Stouf at Tue Nov 25, 2014 08:27
tkaiser replied at Tue Nov 25, 2014 07:47
Thank you for the update. Two questions remain to me:

- how did you measure consumption exactly ( ...


Hi,

I'm quoting myself. This method is for 3.5" display but it should work with 5.0 / 7.0 :

Controlling the backlight is actually very easy.
If we analyse /boot/bananapi/script.bin file, here is what we could find :
  1.     lcd_pwm_used = 1
  2.     lcd_pwm = port:PB02
Copy the Code
So TFT backlight pin is PB02 on A20 SOC.
If we look further in the file, we find :
  1.     gpio_pin_54 = port:PB02
Copy the Code
So it means TFT backlight is actually set on gpio 54.

So if we want to switch off backlight using Python :
  1. import RPi.GPIO as GPIO
  2. GPIO.setmode(GPIO.BOARD)
  3. GPIO.setup(54, GPIO.OUT)
  4. GPIO.output(54, 0)
Copy the Code
If we want to switch it back on :
  1. import RPi.GPIO as GPIO
  2. GPIO.setmode(GPIO.BOARD)
  3. GPIO.setup(54, GPIO.OUT)
  4. GPIO.output(54, 1)
Copy the Code
Unfortunately, this pin doesn’t seem to be controllable as a hardware PWM ouput. It works with software PWM, but it is not very stable (flickering).

From [url=From http://hardware-libre.fr/2014/11 ... play-module-review/]http://hardware-libre.fr/2014/11/banana-pi-3-5-lcd-display-module-review/[/url]

tkaiser  
Edited by tkaiser at Tue Nov 25, 2014 08:45
HWL_Stouf replied at Tue Nov 25, 2014 08:26
Unfortunately, this pin doesn’t seem to be controllable as a hardware PWM ouput. It works with software PWM, but it is not very stable (flickering)


Thank you. Just had a look in the fex file for the 7" display:

There it's GPIO pin 57 instead:
  1. lcd_bl_en_used = 1
  2. lcd_bl_en = port:PH07<1><0><default><1>
  3. lcd_power_used = 1
  4. lcd_power = port:PH08<1><0><default><1>
  5. lcd_pwm_used = 1
  6. lcd_pwm = port:PB02<2><0><default><default>
  7. ...
  8. gpio_pin_55 = port:PH07<1><default><default><default>
  9. gpio_pin_56 = port:PH08<1><default><default><default>
  10. gpio_pin_57 = port:PB02<1><default><default><default>
Copy the Code
What do you mean with unstable/flickering? Isn't it enough to switch the pin off?

Now I had a look into the fex guide and realized that there are options directly addressing the backlight:
  1. lcd_bl_en_used: 0 to disable; 1 to enable
  2. lcd_bl_en: LCD BackLight GPIO configuration
  3. lcd_power_used: 0 to disable; 1 to enable
  4. lcd_power: LCD_VCC Voltage control GPIO configuration
  5. lcd_pwm_used: 0 to disable; 1 to enable
  6. lcd_pwm: lcd PWM, GPIO configuration (PWM0 fixed using the PB02 PWM1 fixed PI03 without user modification)
Copy the Code
Does that mean that I should switch pin 55 also to 0 when I want to disable the backlight?

You have to log in before you can reply Login | Sign Up

Points Rules