Function description
Operating Manual PIT m4SEU
1004648-EN-02
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IDclock
Test pulse line
The signal is generated by the PIT m4SEU and indicates the validity of the
data bits at IDout0 and IDout1.
}
T = 100 ms
}
Duty cycle = 50%
IDout0, IDout1 Data lines for downloading the Key ID number
The PIT m4SEU sends the Key ID number to the controller via these two
data lines.
Each download starts with the MSB.
IDout0:
Send Bit 27 … Bit 14
IDout2
Send Bit 13 … Bit 00
IDin0, IDin1
Data line for reading back the Key ID number
The controller sends the previously received Key ID number back to the
PIT m4SEU via these two data lines.
IDin0:
Receive Bit 27 … Bit 14
IDin1
Receive Bit 13 … Bit 00
Download procedure
[a]
The PIT m4SEU sets the signal at IDsync (control line) to "1" for 100 ms,
thereby signalling to the controller that download has started.
[b]
A rising edge at IDclock (test pulse line) indicates that the data at data lines
IDout0 and IDout1 is present and valid and can be read by the controller.
[c]
By the falling edge at IDclock (test pulse line), the controller must send the
previously read bit back to the PIT m4SEU via the data lines IDi0 and IDi1.
[d]
Before the rising edge at IDclock (test pulse line), the PIT m4SEU reads the
bits sent back to IDi0 and IDi1 by the controller and checks them for equival-
ence.
[e]
At least 60 ms after the falling edge at IDclock (test pulse line), the last bit
sent back by the controller must be present at data lines IDin0 and IDin1.
[f]
A maximum of 100 ms after the falling edge at IDclock (test pulse line), the
last bit sent back by the controller must be present at data lines IDin0 and
IDin1; in other words, by this point at the latest, the data download must be
completed and the data lines must have a "0" signal.
INFORMATION
If the controller does not feed back the previously read bits correctly, the
download is aborted and restarted. The "IDsync" signal is set once again.
The download is repeated until the Key ID number is downloaded in full.
It typically takes 1.8 s to download the Key ID number.
