UR7HCTS2-P840 Datasheet, PDF (7/16 Pages) Semtech Corporation – High-Performance, Low Power PS/2 Touch Screen Controller/Digitizer

PS/2 MODE COMMANDS
When the Reset Command (FFh)
is received, the UR7HCTS2-P840
sets the following default
parameters: Incremental Stream
Mode, 1:1 scaling, report rate of
100 Hz, and disabled. It then
sends AAh to the host followed by
a device ID of 00h.
The Host sends the Resend Last
Data Stream Command (FEh)
when the host detects an error in
any UR7HCTS2-P840 transmission.
The device then resends the last
output data packet to the Host.
This transmission occurs after a
ScreenCoder^TM PS2 transmission
and before the Host enables the
interface allowing the next
ScreenCoder^TM PS2 output.
The Set Default Status
Command (F6h) re-initializes the
device to its condition at power-up.
The Disable Command (F5h)
stops the device from transmitting
all reports. However, the mode
does not change; the
ScreenCoder^TM PS2 is still able to
respond to commands. If the
Disable Command is issued while
the device is transmitting a report,
the UR7HCTS2-P840 immediately
stops the transmission and
disables itself.
The Reset Echo Mode Command
(ECh) returns the device to its
previous mode, and disabled.
The Set Prompt (Remote) Mode
Command (F0h) sets the device
to Prompt Mode. Data values are
then only reported in response to a
Read Report Command (EBh).
If the Set Echo Mode Command
(EEh) is received, the
ScreenCoder^TM PS2 will
immediately return any data bytes
except FFh or ECh.
If the ScreenCoder^TM PS2 is in
Incremental Stream Mode, the
Enable Command (F4h) will allow
it to begin data transmission. If the
device is in Prompt Mode, the
Enable Command will only update
the internal status of the
ScreenCoder^TM PS2.
The ScreenCoder^TM PS2 will
respond to the Set Sampling
Rate Command (F3h) in both
Stream and Prompt Modes but will
only update its internal status if this
command is enacted while the
device is in the Stream Mode.
The UR7HCTS2-P840 responds to
the Read Device Type Command
(F2h) with the device ID of 00h.
The Read Report Command
(EBh) prompts the ScreenCoder^TM
PS2 for a report. The report occurs
even if the device has not moved
or if the status of the switches did
not change.
The Set Incremental Stream
Mode Command (EAh) sets the
ScreenCoder^TM PS2 to Stream
Mode and disables the device.
The Status Request Command
(E9h) returns a 3-byte status
report.
The Set Resolution Command
(E8h) controls resolution, the Set
2:1 Scaling Command (E7h)
enables a coarse/fine tracking
response, and the Set 1:1 Scaling
Command (E6h) enables the
values of movements to be
transmitted to the Host without any
scaling. Due to Semtech’s
Advanced Motion Algorithm, Set
Resolution and Scaling Commands
are acknowledged and reported as
activated, but their status is
ignored.
Copyright ©1999-2001 Semtech Corporation
7
DOC7-TS2-P840-DS-106
www.semtech.com