Adafruit TFT how to power it off?

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richymartin
 
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Joined: Sat May 02, 2015 4:05 am

Adafruit TFT how to power it off?

Post by richymartin »

I have an adafruit TFT connected to my Pi, its great!

Whenever I shut the Pi down the TFT remembers the last thing displayed and by all accounts, seems to remain powered on!

How can I cause the TFT to power off when the Pi Does? Or maybe even power off only the tft by command line?

Thanks in advance

Rich

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richymartin
 
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Joined: Sat May 02, 2015 4:05 am

Re: Adafruit TFT how to power it off?

Post by richymartin »

This is more of a further idea than a post 'bump' I thought about killing the driver but that didnt seem to work either...

pi@raspberrypi /etc/rc0.d $ lsmod
Module Size Used by
evdev 11000 2
joydev 9766 0
stmpe_ts 3847 0
snd_bcm2835 20818 4
snd_pcm 90778 4 snd_bcm2835
snd_seq 61097 0
snd_seq_device 7209 1 snd_seq
snd_timer 23007 2 snd_pcm,snd_seq
snd 66325 10 snd_bcm2835,snd_timer,snd_pcm,snd_seq,snd_seq_device
fb_ili9340 3957 2
fbtft 34434 1 fb_ili9340
syscopyarea 3153 1 fbtft
sysfillrect 3584 1 fbtft
sysimgblt 2278 1 fbtft
fb_sys_fops 1565 1 fbtft
i2c_bcm2708 6200 0
spi_bcm2708 6018 0
uio_pdrv_genirq 3666 0
uio 9897 1 uio_pdrv_genirq

pi@raspberrypi /etc/rc0.d $ sudo rmmod -f fb_ili9340
libkmod: ERROR ../libkmod/libkmod-module.c:753 kmod_module_remove_module: could not remove 'fb_ili9340': Resource temporarily unavailable
Error: could not remove module fb_ili9340: Resource temporarily unavailable

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adafruit_support_mike
 
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Joined: Thu Feb 11, 2010 2:51 pm

Re: Adafruit TFT how to power it off?

Post by adafruit_support_mike »

You're running into the boundary between OS-level control and hardware-level control.

The OS doesn't actually control power to the RasPi PCB, so shutting down the OS doesn't do anything but put the microprocessor in an idle state. To shut off the TFT you need hardware power control, but you can't do that after the OS has halted.

Do you have a TFT breakout or a PiTFT?

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