Dynapro Technologies Dynapro ET TCS, Application Developer'S Manual

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The Polled Touch Mode command selects the Polled Touch Mode, which causes the TCS to
report touchkey closures only when requested (polled) by the host.
The Polled Touch Mode prevents data overruns and lost characters when the TCS is used with a
host that has a slow I/O response. The Polled Touch Mode is also useful when it is undesirable
for the host to use interrupt processing.
The Polled Touch Mode is used in conjunction with the Read Touchkey Status command, which
the host sends to request a touch report. That command is described later in this chapter.
•
When the Polled Touch Mode is reset, the TCS spontaneously sends a touch report to the
host whenever the user touches a touchkey.
•
When the Polled Touch Mode is set, the TCS queues one and only one touch report when the
user touches a touchkey. The TCS sends the report to the host only when the host sends the
Read Touchkey Status command. If multiple touchkeys are touched before the host polls the
TCS for a report, the TCS queues a touch report only for the first touch; the TCS ignores all
other touches, which are in effect locked out.
NOTE
If the TCS receives a Read Touchkey Status command and the user has not touched a touchkey since the
previous Read Touchkey Status command was received, the TCS reports a touchkey number of 000.
If the Touchkey Audible Attribute is set for the touchkey, the TCS beeps immediately when the
touchkey is touched. However, if the TCS has already queued a touch report and is waiting to
send the report to the host, additional touches are ignored and do not cause any visual or audible
feedback.
An auto-repeat rate can be set when the TCS is operating in the Polled Touch Mode. However,
the rate of auto-repeating can be limited by the frequency of the host’s requests for reports. (See
the discussion under "Auto-Repeat Rate Command.") If the host requests touch reports rapidly
enough, the TCS responds at the same auto-repeat rate regardless of whether the Polled Touch
Mode is set or reset.
The TCS takes special action regarding touch activity when the host sends a Build Touchkey,
Clear Touchkey, Touchkey Type, or Copy Screen command that affects the Displayed Screen.
The host must take these actions into account if Polled Touch Mode is set and the host has not
caught up with touchkey input. For details, see the descriptions of each of these commands.
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Reset. (Polled Touch Mode is off.)
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None. (This is a remote command only.)