Le manuel d'utilisateur envoyé par Isamu m'est d'une grande aide
On y apprend beaucoup plus de chose que dans le "pseudo Datasheet" trouvé sur le site Immersion...
Il n'est question que d'un seul modèle de carte, et il est identique à celui que l'on peut voir en photo sur le site GlobalVR par exemple.
Il y a donc d'origine 4 entrées analogiques (potentiomètres pour volant et 3 pédales) ainsi que 2 entrées digitales pour les encodeurs.
Les entrées analogiques sont en 10bits et les digitales en 16bits (mais il est précisé que le traitement interne du signal est en 10bits).
Il y a également un paragraphe qui traite de la course des potentiomètres. De ce que j'ai compris, il est possible, avec des résistances, de modifier la plage d'utilisation des potentiomètres.
Je n'ai pas saisi toutes les explications, mais ça pourrait être une solution en cas d'utilisation d'un potentiomètre multi-tours.
Je vous met le texte original, si les pros comprennent exactement de quoi il s'agit, je suis preneur pour une explication
You can check the voltage polarity versus movements by using the Immersion Studio developer tool or the Windows Control Panel (Game Controllers).
The IPCB-6054 PCB also contains conditioning electronics that may be used to expand the dynamic range of an analog input sensor. This is useful for the case where a potentiometer may only move through a small portion of its range of travel. For example: if a 300° pot is used in a joystick that only moves +/- 30°, it is only utilizing 20% of its range. If a 3.3 volt signal is used across the device, the output swing might be 1.2 to 2.2 volts, significantly less than the desired 0.0-3.3 volt full swing signal. The Immersion microcontroller can perform auto-scaling to compensate for this reduced range, but the resolution will then suffer.
The ideal way to compensate for this reduced range is to use the amplifier built into the signal conditioning circuit. By selecting the correct resistors [R160 & R152 for X-axis (wheel position); R170 & R171 for Y-axis (brake), R94 & R91 for Z-axis (throttle); R137& R149 for W-axis (clutch or rudder)], the sensor range can be expanded as governed by the following formulas:
Gain(x) = 1 + (R160/R152)
Gain(y) = 1 + (R170/R171)
Gain(z) = 1 + (R94/R91)
Gain(w) =1 + (R137/R149)
In the example above, selecting R160 and R170 to be 20KΩ resisters and R152 and R171 to be 10KΩ, will yield a gain of 3.0. This would have the effect of expanding the output range from 1.0 volt to 3.0 volts, also centered about 1.7V; yielding an output of 0.2 to 3.2 volts. It is important to realize that this gain stage will also amplify the deviation from center position, so a misalignment of 0.2 volts (center of 1.9 instead of desired 1.7) would be increased to 0.6 volts (center of 1.9v, range of 0.7 to 3.3V saturation). If you can not accurately dial in the center position, you may need to decrease your gain to ensure that neither end of the sensor saturates.
The unity gain configuration of the IPCB-6054 board is achieved by leaving R152, R171, R91, and R149 open.
J'attends la confirmation d'Immersion, et selon le tarif, je commande !
