bar graph driver
FORTH mini system
If the bar graph of the
emulator is an addressable register in
the extension registers area of the FORTH core described as follows:
bit 0 is corresponding to the left green indicator
bit 15 is corresponding to the right red indicator
lit indicator if value=1
The driver will allow to facilitate the use of this registes while
use of the real-time kernel. The principle consists in making i
possible the developer to indicate the desired level without to have to
manage the peak value memory effect.
the FORTH mini system emulator, the 16 indicators of the bar graph are
wired on the components PCF8574 and PCF8574A of I2C port numero 2. The bit 7 of the PCF8574 is corresponding to the left green indicator and the bit 0 of the
PCF8574A to the right red indicator. The electrical schematic is the following:
- CW_BARRE_GRAPHE 277
Numero of the bar
graph extension register.
This instruction does not exist in the FORTH mini system,
The access to the indicators is made with the instructions I2C_PCF8574_C@, I2C_PCF8574_C!, I2C_PCF8574A_C@ and I2C_PCF8574A_C! numero 2.
Displaying of the
niveau is the value of the desired level (0 minimum to 16 maximum).
If niveau is negative, the driver task is cleared.
driver not being integrated into the kernel, it is initially necessary
to compile the source file barre_graphe.txt
before being able to use it.
For the FORTH mini system, it is initialy necessary to compile first the I2C drivers described in the source files pcf8574.txt and pcf8574a.txt then compile barre_graphe.txt.
The following sequence is corresponding to the displaying of level 10:
automaticaly the task installation which memorizes the maximum level
during 250 ms. This is
realized with priority 49152. This task is cleared when the level is negative.
The following program uses the analogical
input output of the emulator and needs also the installation of the
source file analogique.txt before to be able to use it:
( Absolute value of the input and division by 8 for the bar
ABS DUP 4/ 2/ BARRE_GRAPHE
PROG_ANALOGIQUE 2000 SYNC_ANALOGIQUE
To remove this
program, it is enough to make:
BARRE_GRAPHE DUP SYNC_ANALOGIQUE
Here is a video: