KMA215 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
Product data sheet Rev. 1 — 24 February 2014 29 of 50
NXP Semiconductors
KMA215
Programmable angle sensor with SAE J2716 SENT
13. Programming
13.1 General description
The KMA215 provides an OWI to enable programming of the device which uses
pin OUT/DATA bidirectionally.
In general the device runs in digital output mode, the normal operation mode.
The embedded programming data configures this mode. After a power-on reset once time
t
on
has elapsed,it starts. In this mode, the magnetic field angle is repeatedly transmitted
with SENT protocol.
A second mode, the command mode enables programming. In this mode, the customer
can adjust all required parameters (for example zero angle, angular range, SENT
configurations) to meet the application requirements. The data is stored in the non-volatile
memory. After changing the contents of the memory, recalculate and write the checksum
(see Section 13.4
).
In order to enter the command mode, keep OUT/DATA pin HIGH for at least t
to
and send a
specific command sequence after a power-on reset and during the time slot t
cmd(ent)
. The
external source used to send the command sequence must overdrive the output buffer of
the KMA215. In doing so, it provides current I
od
.
During communication, the KMA215 is always the slave and the external programming
hardware is always the master. Figure 15
illustrates the structure of the OWI data format.
The master provides the start condition, which is a rising edge after a LOW level. Then
a command byte which can be either a read or a write command is sent. Depending on
the command, the master or the slave has to send the data immediately after the
command sequence. If there is a read command, an additional handover or takeover bit is
inserted before and after the data bytes. The master must close each communication with
a stop condition. If the slave does not receive a rising edge for a time longer than t
to
,
a time-out condition occurs. The bus is reset to the idle state and waits for a start condition
and a new command. This behavior can be used to synchronize the device regardless of
the previous state.
All communication is based on this structure (see Figure 15
), even for entering the
command mode. In this case, the write command 94h and the signature are required.
The customer can access the non-volatile memory, CTRL1, TESTCTRL0 and
SIGNATURE registers (described in Section 13.5
). Only a power-on reset leaves the
command mode. A more detailed description of the programming is given in the next
sections.
Fig 15. OWI data format
001aag742
write
IDLE IDLESTART STOPCOMMAND DATA BYTE 1 DATA BYTE 2
IDLE START COMMAND HANDOVER TAKEOVER STOP IDLEDATA BYTE 1 DATA BYTE 2
read
