petrkr / it8951usb

Original fork from https://git.sr.ht/~martijnbraam/it8951

IT8951 e-paper controller

This is a small utility to send images to an e-paper display using an IT8951 controller like the waveshare e-paper hat. Instead of using the i2c, i80 or spi interface this uses the USB interface that is normally used with the E-LINK TCON DEMO windows application.

The usb interface of the IT8951 controller shows up as an usb mass storage device with no medium inserted (similar to SD card readers). The display is controlled by sending customer-defined SCSI commands. For access to device you need add user to group disk or use sudo (NOT RECOMMENDED!!).

Actuall version works only with full-width images (for example 1024 per line)

Building

$ mkdir build
$ cd build
$ cmake ..
$ make

Make sure user is in disk group

$ id

Usage

Clear the display
$ ./it8951 -c /dev/sdb 0 0 1024 758

Send an 8-bit grayscale image (full size 1024 x 758)
$ ./it8951 /dev/sdb 0 0 1024 758 < image.raw

Generate an image and display it
$ convert -background white -fill black \
  -font Ubuntu -pointsize 50 label:"$(date)" \
  -gravity Center -extent 1024x758 \
  -depth 8 gray: \
  | ./it8951 -d /dev/sdb 0 0 1024 758

it8951usb's Issues

any plans to add a bmp to raw converter to it8951usb?

ImageMagick is a wonderful huge swiss knife ;-) that needs more space than a raspberry pi or beagle bone like to give.

I am looking for this kind of use case:

1. app creates a bmp file on disk
2. who does the bmp to byte array conversion?
3. it8951usb does the transfer

Any hints or tool recommendations?

IT8951 and beaglebone

build it8951 works on beaglebone black without issues.

dmesg shows some entries about this mass storage and disable it

any hints howto get this device enabled?

Increase MAX_TRANSFER and gain up to 23%

Hi,

now running with #define MAX_TRANSFER 120*1024 which gives me a improvement up to 25%

time it8951 -c /dev/sda 0 0 1024 758
Filling buffer by dummy data (length 776192)
Start offset: 0
Apply some h-offset)
display area (0x00195870)
Updating
  Area X: 0x00000000
  Area Y: 0x00000000
  Area W: 0x00000400
, Area H: 0x000002f6

real	0m4.481s
user	0m0.000s
sys	0m0.016s

# MAX_TRANSFER 120*1024
time it8951d -c /dev/sda 0 0 1024 758
Filling buffer by dummy data (length 776192)
Start offset: 0
Apply some h-offset)
display area (0x00195870)
Updating
  Area X: 0x00000000
  Area Y: 0x00000000
  Area W: 0x00000400
, Area H: 0x000002f6

real	0m3.444s
user	0m0.000s
sys	0m0.012s

Did you figure out some optimizations for quicker transfer?

Edit: But not as stable as expected, maybe the firmware need to bee updated to handle larger transfer size too?

Have you tried the raw mode update ?

infos from https://www.waveshare.net/w/upload/1/18/IT8951_D_V0.2.4.3_20170728.pdf

Added 0xA5 - Fast Write Memory command for load full image

In this version, we added the following new commands:
Fast write memory command 0xA5 which is for fast load full width image
(continuous pixels data) and it the transfer rate may speed up to Max:
30MB/Secs.

I tried the WaveShare Tool to upload images and it was much faster.

.bmp to .raw

Can you please explain which command was used to convert tesline.bmp to testline.raw?

Is it possible to blank the screen white instead of gray?

Using ./it8951 -c -m 0 /dev/sda 0 0 1024 768to blank the screen and it turns out gray.

What am i missing?