© Quantum Research Group Ltd.
Due to the large number of bytes written to eeprom by this
5.5 Supervisory / System Functions
Supervisory functions report or control miscellaneous
functions that affect overall chip control, testing, or
diagnostics. All supervisory functions ignore scope except
where noted.
command, there is a significant delay from the second byte
until the return echo is sent back to the host.
This command should be used only during production. There
is no get version of the command.
For commands requiring Put mode to operate, the device
should be set back to Get mode immediately thereafter where
possible, to help prevent unintended writes to eeprom.
b
0x62 - RECALIBRATE
K
Bytes / Cmd 2nd Byte Range
EYS
Scope
1, 8, 64
n/a
Returns
0x62
n/a
Put
Get
1
n/a
n/a
n/a
6
0
X
36 - EEPROM
CHECKSUM
Bytes / Cmd # Bytes Rtnd
Scope
n/a
n/a
Returns
n/a
0x00..0xFF
Section 2.10, p. 8; Section 3.16
Put
Get
n/a
1
n/a
1
Lowercase 'B'. This is a put-only command that causes the
keys selected by scope to recalibrate. The part must be in Put
mode for this command to work.
See page 22.
44 - DAC TEST
The return byte is sent before the keys have calibrated. While
keys are in recalibration, status of the keys can be
determined using the 'e' or 'E' commands.
D
0
X
Scope
n/a
n/a
Bytes / Cmd 2nd Byte Range
0x00..0xFF
n/a
Returns
0x44
n/a
Put
Get
2
n/a
If 'b' is sent while key(s) are already in the middle of
recalibration, the affected key(s) will abandon the old
calibration cycle and start a new one.
Uppercase 'D'. Enables the DAC test mode function. The
second byte contains the value to be sent to the DAC, which
must be sent within 100ms to the part otherwise the
command is automatically cancelled. The part must be in Put
mode for this command to work.
There is no get version of the command.
l
0x6C - RETURN
Scope
L
AST
C
Bytes / Cmd
OMMAND
C
# Bytes Rtnd
HARACTER
Returns
n/a
0x00..0xFF
Put
Get
n/a
n/a
n/a
1
n/a
1
This function can be used to test the external R2R DAC for
proper operation during board production or in development.
Once in this mode the part ceases to operate as a sensor,
and must be reset via power-down or the reset pin to restore
normal operation. This function does not persist past reset or
power-down.
Lowercase 'L'. This get-only command reports back with the
value of the prior command received by the part. The
command also reports back any erroneous commands,
allowing the host device to verify that a command was
correctly received.
Before the DAC value is set in hardware, the burst length on
all keys is set to 0 to disable keys and prevent further
scanning. All keys will then report errors until all burst lengths
are again set by the host after the part has been reset.
If this command is repeated, the second and subsequent
instances of 'l' will report back with 0x6C.
There is no put version of the command.
A series of 'D' commands can be sent to cause the DAC to
generate a ramp or other test pattern which can be easily
diagnosed on an oscilloscope.
r
0x72 - RESET
Scope
D
EVICE
Bytes / Cmd 2nd Byte Range
Returns
0x72
n/a
There is no get version of the command.
Put
Get
n/a
n/a
2
n/a
0x00
n/a
L
0x4C - LOCK
Scope
R
EFERENCE
L
Bytes / Cmd 2nd Byte Range
EVELS
Section 3.14, p. 14
Returns
0x4C
n/a
Put
Get
64
n/a
2
n/a
0x00
n/a
Lowercase 'R'. This put-only command hard-resets the part.
The command 0x72 must be followed by a null (0x00) within
100ms or the command will fail. The part must be in Put
mode for this command to work.
Section 2.8, p. 7
Uppercase 'L'. This is a put-only command that locks the
reference levels of the device into eeprom for all keys, for
boundary checking purposes over the product's life.
After the null byte is received, the device will echo back the ‘r’
character; about 16ms after the echo the part will reset.
Upon waking up again, the part will resume communication
and sensing in accordance with the timing shown in Section
3.16.
The whole command – 'L' followed by a null (0x00) - must be
received within 100ms without any intervening byte, or the
command will fail. The part must be in Put mode for this
command to work.
If for some reason the device is unable to echo back the ‘r’
character, for example due to the host not releasing the SS
line, the part will completely reset anyway after about 2
seconds.
The scope of this command is always 'all keys'.
This function records to eeprom the Cz values, DAC offset,
and signal reference. The locked reference levels are used to
compute boundary checks; these are performed after the next
device recalibration or reset.
There is no get version of the command.
lQ
28
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