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3.6.6
Margin Voltage Check
The threshold voltage of EEPROM cells is dependent on the programming voltage and programming pulse length.
For reliable programming the programming pulse has to be kept within the specification
interface. The margin command can be used to check the threshold voltages of the programmed cells:
To check the cells programmed to '1', a voltage V
E
). For EEPROM cells with a threshold voltage smaller than the applied V
H
EEPROM registers, for those with a higher threshold voltage, a '1' will be written. By sweeping the applied V
the actual threshold voltages of each EEPROM cell can be identified.
In order to check the threshold voltages of EEPROM cells programmed to '0', it is necessary to activate the "Margin
zero on" bit in the TEST register before sending the margin check command. Also for the '0' cells, the actual
threshold voltages of each EEPROM cell can be identified, by sweeping the applied V
3.6.7
DATA access example
Following steps are required to readout other internal data like the calibrated temperature and Hall value (as
shown below in
Table
should be set to '1').
Optionally do a last status
readout (adr. 0x0F) to check
the IF mode is still active
and the device is ok.
Figure 3-15 Basic data access flow
Flowchart description:
1.
Switch on the device
2.
Send an inital command (status register readout)
3.
Read the status data,check that the device is valid and the EEPROM content is valid
4.
Set the test register: DSP stop=1 (see previous chapter)
5. Set the test register: DSP stop=1 DSP off=1 (see previous chapter)
6. Send a read command (HCAL)
– Read the data word
User's Manual
3-15). This routines can also be used for an EEPROM access (in that case also FECoff
EEPROM
programming
V
= 5V
dd
INIT-CMD:
cmd=0x01
adr=0x0F
READ DATA
Is
0xF93D or
0xFB3D ?
CMD (write):
cmd=0x09
adr=0x21
DAT: 0x0800
(DSP stop)
CMD (write):
cmd=0x09
adr=0x21
DAT: 0x0C00
(DSP stop,
DSP off)
CMD (read)
cmd=0x01
adr=0x05
READ DATA
V
= 0V (off)
dd
FINISHED
is applied after the margin check command (Command
O,MARG
NO
Like reading out H_CAL,
also all other RAM and
EEPROM registers can
be read out here in a loop.
17
TLE4997
User's Manual
TLE4997 Programming
(Table
3-5) at the sensor
, a '0' will be stored to the
O,MARG
.
O,MARG
ILLEGAL
STATUS:
analyse
problem
v01_01, 2019-08
,
O,MARG
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