Hi,
On Sun, 31 Mar 2013 02:30:00 -0700 (PDT) bhargavak anur.bhargav@gmail.com wrote:
Hi
Thank you for that heads up. In one of posts above a reference to the following code fragment is made, it uses a fatload command
For example, this is the whole "code" for a slide show demo I've been using on a number of trade shows:
bootdelay=6 show_one=fatload mmc 0:2 40001000 slide-${i}.bmp;bmp d 40001000 slide_show=while mmc rescan; do for i in 1 2 3 4 5 6 7 8 ; do runshow_one ; sleep ${delay} ; done ; done bootcmd=run slideshow
Can you please explain the "show_one" and the "slide_show" commands ? And, do I just put this into board config ?
"show_one" and "slide_show" are environment variables containing a sequence of U-Boot commands. These can be executed by "run show_one" or "run slide_show".
When "show_one" is executed, U-Boot runs two commands:
fatload mmc 0:2 40001000 slide-${i}.bmp
and
bmp display 40001000
The first command loads a file (i.e. "slide-0.bmp") into SDRAM memory at address 0x40001000. It loads the file from the MMC/SD-Card which is connected to the first available SD-Card controller. The file is loaded from the second partition on the SD-Card which is a FAT partition (therefore fatload command). The "${i}" in the file name is used to be able to load images with different file names when this command is executed in a loop.
The second command reads the image at address 0x40001000 in SDRAM, decodes the image data and copies it into the frame buffer.
"slide_show" command is a loop which test for SD-Card presence ("mmc rescan") and executes another inner loop in which the "show_one" command is running 8 times with index "i" counting from 1 to 8 (so that 8 different images are loaded into SDRAM while each loop iteration). After each load/display operation in the loop the execution of the next loop iteration is delayed by the amount of seconds specified in the "delay" environment variable.
Note that these loops will only work if U-Boot was built with enabled CONFIG_SYS_HUSH_PARSER in the board configuration.
You normally won't put these commands into board config. You have to setup the environment variables on the U-Boot command line using "setenv" command and save them using "saveenv" command.
HTH,
Anatolij
