IC-TW14 Datasheet, PDF (12/33 Pages) IC-Haus GmbH – IC-PMX Companion Chip

iC-TW14
iC-PMX Companion Chip
Rev A1, Page 12/33
Serial Communication Errors
If the serial read or write command contains invalid
hexadecimal digits or is the wrong length, the iC-TW14
responds with
:Exdd!
where x is R or W for a read or write command (re-
spectively) and dd is the invalid command data (which
may be any length). Valid hexadecimal digits are 1 –
9 and A – F. A valid read command contains exactly 5
characters; a valid write command contains exactly 9
characters.
If the character after the packet start character (:) is
neither R nor W, or if lower-case characters are used in
the command packet, the iC-TW14 responds with
:Udd!
See Figure 15 and Table 8 in iC-PMX application note
2 for the definitions of the four Wiegand pulse points (J,
K, L, and M).
The Wiegand pulse voltage (vvvv) is measured at
iC-TW14 pin VWP, which must be connected to iC-PMX
pin VWC via a voltage divider to avoid overdriving VWP.
The Wiegand pulse voltage is a positive hexadecimal
value in mV.
The magnetic field strength (hhhh) when the Wiegand
pulse occurs is measured by reading iC-PMX single-
turn Hall sensors H1 and H3 since the iC-PMX phase
sequence Hall sensors (H4 and H5) cannot be read
directly. The magnetic field strength is a hexadeci-
mal 16-bit 2’s-complement value in units of 0.1 kA/m
equal to H1 if iC-PMX configuration input C2 is low,
and (H1 – H3) if C2 is high. See Self-Sustained Opera-
tion Mode Selection in the iC-PMX datasheet for more
information.
where dd is the command data (which may be any ^{The Wiegand pulse angle (aaa) is a positive hexadeci-}
length).
mal value in degrees (0x000 – 0x167).
Diagnostic Mode 1
Diagnostic mode 1 is used to measure the Wiegand
pulse angle, voltage, and magnetic field strength when
a Wiegand pulse occurs. Diagnostic mode 1 is initiated
by writing 1 to MODE/CMD (see page 19 for more in-
formation). See DIAGNOSTIC MODES on page 26 for
information on using diagnostic mode 1.
With diagnostic mode 1 active, a packet containing
the Wiegand pulse angle, voltage, and magnetic field
strength is returned by the UART whenever a Wiegand
pulse occurs.
For example, if a Wiegand pulse M occurs at 23° with a
voltage of 7.46 volts, a VWP voltage divider of 1/3, and
a field strength of 10 kA/m at 27 °C, the iC-TW14 sends
:M09B60064017!
If the iC-TW14 is busy sending a diagnostic mode 1
packet when a Wiegand pulse occurs, it sends
:ED!
Diagnostic Mode 1 Packet (:pvvvvhhhhaaa!)
Character Description
:
Packet Start
p
Wiegand Pulse Point (J, K, L, or M)
vvvv
Wiegand Pulse Voltage (hex mV)
hhhh
Magnetic Field Strength (hex units of 0.1 kA/m)
aaa
Wiegand Pulse Angle (hex degrees)
!
Packet End
Table 6: Diagnostic Mode 1 Packet
following the current packet. This indicates that the
data from the second Wiegand pulse has been lost.