flashing screen

[jfs10]

I have the old adafruit 2.2 display. I believe it is working. I have all the right things in the logs. When I run some of the examples to test the screen, the screen just flashes. Normally it is dark, but when I run a test it flashes white. I never see anything drawn to the screen. I don't see any errors, and in fact the fbtest program says that it passed everything. Any ideas?

[notro]

You can try and lower the speed:

modprobe fbtft_device name=adafruit22 speed=16000000

This is the expected sequence of events: Before driver loading, the backlight should be on and the display white. During driver loading, the backlight should be turned off, then on, and the display should be black.

[jfs10]

I will give changing the speed a try.

The sequence you have described is what I see.

Attempts to control the backlight myself have failed. I have tried the following commands without success: echo "0" > /sys/class/backlight/fb_hx8340bn/bl_power echo "1" > /sys/class/backlight/fb_hx8340bn/bl_power

Here is the results of executing dmesg after adding speed=16000000 to /etc/modules and rebooting.

[ 5.203149] bcm2708_spi bcm2708_spi.0: DMA channel 0 at address 0xf2007000 with irq 16 [ 5.348226] usbcore: registered new interface driver snd-usb-audio [ 5.369606] bcm2708_spi bcm2708_spi.0: DMA channel 4 at address 0xf2007400 with irq 20 [ 5.475429] bcm2708_spi bcm2708_spi.0: SPI Controller at 0x20204000 (irq 80) [ 5.559049] bcm2708_spi bcm2708_spi.0: SPI Controller running in dma mode [ 5.688665] Registered led device: led0 [ 7.404060] usbcore: registered new interface driver rtl8192cu [ 11.946330] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [ 12.497967] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [ 13.261396] fbtft_device: Deleting spi0.0 [ 13.389459] fb_hx8340bn spi0.0: setup: invalid bits_per_word 9 (must be 8) [ 13.408414] fb_hx8340bn spi0.0: 9-bit SPI not available, emulating using 8-bit. [ 14.214369] graphics fb1: fb_hx8340bn frame buffer, 176x220, 75 KiB video memory, 16 KiB buffer memory, fps=20, spi0.0 at 16 MHz

I am a work, so I can tell if adding that line made a difference. I will run the fbtest program when I get home.

thanks

On Sun, Dec 1, 2013 at 11:53 AM, notro notifications@github.com wrote:

You can try and lower the speed:

modprobe fbtft_device name=adafruit22 speed=16000000

This is the expected sequence of events: Before driver loading, the backlight should be on and the display white. During driver loading, the backlight should be turned off, then on, and the display should be black.

— Reply to this email directly or view it on GitHubhttps://github.com/notro/fbtft/issues/54#issuecomment-29577369 .

[jfs10]

I tired last night, without success. It just flashed. It does not appear that anything is drawn to the screen.

On Mon, Dec 2, 2013 at 7:47 AM, jonathan swaby jfswaby@gmail.com wrote:

I will give changing the speed a try.

The sequence you have described is what I see.

Attempts to control the backlight myself have failed. I have tried the following commands without success: echo "0" > /sys/class/backlight/fb_hx8340bn/bl_power echo "1" > /sys/class/backlight/fb_hx8340bn/bl_power

Here is the results of executing dmesg after adding speed=16000000 to /etc/modules and rebooting.

[ 5.203149] bcm2708_spi bcm2708_spi.0: DMA channel 0 at address 0xf2007000 with irq 16 [ 5.348226] usbcore: registered new interface driver snd-usb-audio [ 5.369606] bcm2708_spi bcm2708_spi.0: DMA channel 4 at address 0xf2007400 with irq 20 [ 5.475429] bcm2708_spi bcm2708_spi.0: SPI Controller at 0x20204000 (irq 80) [ 5.559049] bcm2708_spi bcm2708_spi.0: SPI Controller running in dma mode [ 5.688665] Registered led device: led0 [ 7.404060] usbcore: registered new interface driver rtl8192cu [ 11.946330] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [ 12.497967] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [ 13.261396] fbtft_device: Deleting spi0.0 [ 13.389459] fb_hx8340bn spi0.0: setup: invalid bits_per_word 9 (must be 8) [ 13.408414] fb_hx8340bn spi0.0: 9-bit SPI not available, emulating using 8-bit. [ 14.214369] graphics fb1: fb_hx8340bn frame buffer, 176x220, 75 KiB video memory, 16 KiB buffer memory, fps=20, spi0.0 at 16 MHz

I am a work, so I can tell if adding that line made a difference. I will run the fbtest program when I get home.

thanks

On Sun, Dec 1, 2013 at 11:53 AM, notro notifications@github.com wrote:

You can try and lower the speed:

modprobe fbtft_device name=adafruit22 speed=16000000

This is the expected sequence of events: Before driver loading, the backlight should be on and the display white. During driver loading, the backlight should be turned off, then on, and the display should be black.

— Reply to this email directly or view it on GitHubhttps://github.com/notro/fbtft/issues/54#issuecomment-29577369 .

[notro]

I just tried my display with the latest kernel to make sure it still works. I also tested the backlight control. To be sure: you have RST wired to GPIO25 (P1-22) and BL to GPIO23 (P1-16)? And you get a black display (not white) with backlight ON when to load the device/driver?

[jfs10]

It was indeed my connections. GPIO25 not pin 25. I checked the wiring several times. If you had left off the P1-22, I think I would have still missed it.

Everything is working correctly now. Thank you for your patience.

Thanks

On Thu, Dec 5, 2013 at 1:53 PM, notro notifications@github.com wrote:

I just tried my display with the latest kernel to make sure it still works. I also tested the backlight control. To be sure: you have RST wired to GPIO25 (P1-22) and BL to GPIO23 (P1-16)? And you get a black display (not white) with backlight ON when to load the device/driver?

— Reply to this email directly or view it on GitHubhttps://github.com/notro/fbtft/issues/54#issuecomment-29925776 .