mc33789 Freescale Semiconductor, Inc, mc33789 Datasheet - Page 60

• Manufacturer Part Number: mc33789
• Description: Airbag System Basis Chip Sbc With Power Supply And Psi5 Sensor Interface
• Manufacturer: Freescale Semiconductor, Inc

Table 25. SPI Command, - T_UNLOCK
FUNCTIONAL DEVICE OPERATION
SENSOR MESSAGE, OPERATION COMMAND AND SPI
SAFE_THx (0x45 ~ 0x4C, 0x85 ~ 0x8C)
for reading and writing the 8 safing threshold values.
following conditions are all met:
and requires no prior unlock message.
using the eight commands as shown in
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33789
Read *
Write
The SAFE_THx command is a read/write command used
Writing of the safing thresholds can be enabled only if the
•The previously received message was a T_UNLOCK
•The Unlock code in the T_UNLOCK command is correct
•The Safing state machine is in Start-up mode
Reading of the safing thresholds is enabled in any state,
A total of eight safing thresholds can be read or written
command
per definition
SO **
SO
SO
SI
SI
* The Read response will always be ERROR with the RE bit set to ‘1’
** The response to a Write while not in Start-up Mode results in ERROR with RE = 1
15
0
0
0
1
0
UNLOCK
U7:U0
14
1
0
0
0
0
8-bit key value for safing threshold update
13
0
1
0
0
0
12
Table
P
P
P
0
0
26.
11
1
1
1
1
1
Function
T_UNLOCK (0x4D, 0x8D)
10
1
1
1
1
1
9
0
1
1
0
1
8
1
0
0
1
0
U7
7
0
0
x
0
U6
6
0
0
0
x
U5
5
0
0
x
0
Analog Integrated Circuit Device Data
U4
4
0
0
0
x
Freescale Semiconductor
U3
3
0
0
x
0
U2
2
0
0
0
x
U1
1
0
1
x
1
U0
0
0
0
0
x