User's Manual

7.5 Modiﬁcation of non-volatile parameters

The non-volatile parameters are also called UserSettings and are stored in a special ﬂash

location. This settings can also be conﬁgured using our windows pc software "ACC".

7.5.1 CMD_SET_REQ

This command enables direct manipulation of the parameters in the module’s non-volatile

UserSettings. The respective parameters are accessed by means of the corresponding

SettingsIndex. Parameters with size of two or more Bytes have to be transferred with the

LSB ﬁrst unless otherwise speciﬁed.

The modiﬁed parameters only take effect after a restart of the module. This

can be done by a

CMD_RESET_REQ

or using the /RESET pin.

The validity of the speciﬁed parameters is not veriﬁed by the application. In-

correct values can result in device malfunction up to a scenario where the

ﬁrmware of the module needs to be re-ﬂashed to get it operating again!

Any use of

CMD_SET_REQ

will consume one ﬂash erase/write cycle. Flash

erase/write cycles are limited through hardware (guaranteed minimum 100k

cycles). For frequently changing parameters use the volatile parameters "Run-

timeSettings", see chapter

7.4

To store the parameters in the ﬂash memory of the module, the particular mem-

ory segment must be buffered into RAM, then to be erased entirely and then

restored from RAM.

If a reset or VCC instability occurs during this procedure (e.g. due to sup-

ply voltage ﬂuctuations), the entire memory area may be destroyed and the

module can only be resurrected by means of a JTAG or Bootloader ﬁrmware

update.

Recommended procedure: First verify the conﬁguration of the module with

CMD_GET_REQ

and only apply a

CMD_SET_REQ

if required. Make sure the VCC is

stable and no reset occurs during this procedure.

Format:

Start signal Command Length SettingsIndex Parameter CS

0x02 0x09 1 Byte 1 Byte (Length - 1) Bytes 1 Byte

Response (

CMD_SET_CNF