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Data Sheet - D e t a i l e d D e s c r i p t i o n
7.6 Programming the AS5140H
A detailed description of the austriamicrosystems low voltage polyfuse OTP programming method is given in Application Note AN514X-
10, which can be downloaded from the austriamicrosystems website. The OTP programming description in this datasheet is for general
After power-on, programming the AS5140H is enabled with the rising edge of CSn with Prog = high and CLK = low. The AS5140H programming
is a one-time-programming (OTP) method, based on polysilicon fuses. The advantage of this method is that a programming voltage of only 3.3V
is required for programming. The OTP consists of 52 bits, of which 21 bits are available for user programming. The remaining 31 bits contain
factory settings and a unique chip identifier (Chip-ID).
A single OTP cell can be programmed only once. Per default, the cell is “0”; a programmed cell will contain a “1”. While it is not possible to reset
a programmed bit from “1” to “0”, multiple OTP writes are possible, as long as only unprogrammed “0”-bits are programmed to “1”. Independent
of the OTP programming, it is possible to overwrite the OTP register temporarily with an OTP write command at any time. This setting will be
cleared and overwritten with the hard programmed OTP settings at each power-up sequence or by a LOAD operation.
The OTP memory can be accessed in several ways:
Load Operation: The Load operation reads the OTP fuses and loads the contents into the OTP register. Note that the Load operation is
automatically executed after each power-on-reset.
Write Operation: The Write operation allows a temporary modification of the OTP register. It does not program the OTP. This operation can
be invoked multiple times, and will remain set while the chip is supplied with power and while the OTP register is not modified with another
Write or Load operation.
Read Operation: The Read operation reads the contents of the OTP register, for example to verify a Write command or to read the OTP
memory after a Load command.
Program Operation: The Program operation writes the contents of the OTP register permanently into the OTP ROM.
Analog Readback Operation: The Analog Readback operation allows a quantifiable verification of the programming. For each pro-
grammed or unprogrammed bit, there is a representative analog value (in essence, a resistor value) that is read to verify whether a bit has
been successfully programmed or not.
7.6.1 OTP Memory Assignment
Table 19. OTP Bit Assignment
Incremental Output Mode Selection
10 bit Zero Position