© Quantum Research Group Ltd.
5.1 Direction Commands
5 Commands & Functions
Setup commands can be used to either send control
information to the part for programming into its internal
eeprom, or to extract the current setting of this information.
The same Setup function can do either. To accomplish this
the device relies on direction control via the Get and Put
commands. In Get mode, a Setup command will return
information. In Put mode, the behavior of the device is
altered, and often a second operand byte must be sent.
The command structure is designed to minimize control and
data traffic. All repetitive data and status commands from the
host are single-byte, and most commands result in single-
byte device responses. Behavioral setup commands involve
multiple bytes but these are infrequently used.
Special 'scope' commands exist to restrict subsequent
commands to a specific key or range of keys. This control
structure permits most matrix keys, which are usually
identical in shape and size, to be programmed 'in bulk' using
a 'global' scope command, followed by a scope restriction to
specific key(s), followed by more key programming, to
prevent the need for tedious key-by-key programming across
an entire matrix.
The powerup or reset default mode is Get. The current
Get/Put mode persists until countermanded by a different
Get/Put command or until the device is reset or powered off.
It is advisable to use Put mode only when actually writing
Setups to the device, which will happen infrequently; the part
should normally be left in Get mode. Get mode acts as a lock
to prevent accidental changes to the internal eeprom.
There are four types of commands:
Direction - Determine whether subsequent commands are
used to get data from or put data to the part;
Multiple direction commands of the same type (g, g, g, g ...)
are harmless and can be used to insure that the part does not
accidentally enter Put mode for a prolonged period, for
example due to noise glitches on the SPI lines. The 'g'
command can be repeated every few seconds.
Scope - Restrict the range of effect of subsequent
commands to a specific set of keys;
Status - Cause the part to respond with key information,
such as detections, signals, error codes, and the like;
g
0
X
67 - GET
Scope
n/a
C
OMMAND
Setup - Modify functionality such as burst length, threshold
levels, drift compensation characteristics, etc.
Bytes / Cmd 2nd Byte Range
Returns
0x67
n/a
Put
Get
1
n/a
n/a
n/a
Supervisory - Special functions such as diagnostics,
calibration, etc. which affect the part as a whole.
n/a
Lowercase 'G'. The 'g' command causes the device to treat all
subsequent Setup commands as 'Gets'; after, when a Setup
command is received from the host the part will respond by
sending back the current status of that Setup parameter.
All command types can be intermixed. Even during normal
device operation it is possible to use Setup and Supervisory
functions to alter key behavior on the fly. There is no special
'setup mode'.
The 'g' command is always single-byte and echoes back
itself.
Get/Put, Scope, and many Supervisory functions are volatile
and do not persist after a power down or reset cycle. Some
Supervisory commands require that the part be reset in order
for the new settings to take effect.
p
0
X
70 - PUT
Scope
n/a
C
OMMAND
Bytes / Cmd 2nd Byte Range
Returns
0x70
n/a
Note that the Setup functions write to eeprom and require
extra time for a response back to the host. Also note that as
with all eeprom memories there is a recommended lifetime
limit to the number of writes; this limit is 100,000 cycles.
Put
Get
1
n/a
n/a
n/a
n/a
Lower case 'p'. The 'p' command causes the device to treat
all subsequent Setup commands as 'Puts'; after, when a
2-byte Setup command is received from the host the part will
respond by programming in the desired parameter for the
key(s) which are affected.
Command functions are summarized in Section 5-6
It is highly advised to test the device checksum
(command ‘6’) or individual key settings or the general
device status (‘7’) once Setups have been programmed
into the part, each time the part is powered up and
periodically while running.
The 'p' command is always single-byte and echoes back
itself.
The part backs up all eeprom locations into Flash
memory, from which data is restored automatically
following a reset if eeprom corruption is detected. The
part should also be reset after any Put command(s) in
order to force the copy of eeprom data into Flash. See
Section 4.6.
lQ
20
www.qprox.com QT60xx5B / R1.06
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