ETAS
Hardware Description
BR_XETK-S3.0
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User Guide
24
4.7
Data Emulation and Data Measurement
The BR_XETK-S3.0 is a serial XETK using DAP as the primary microcontroller
interface. Typical of all serial (X)ETKs, the RAM used for data emulation and
data measurement is not accessible by the XETK until the microcontroller is
powered up and the startup handshake is performed.
Serial XETKs use the ETAS two page concept, consisting of both a Reference
and a Working page.
The Reference Page is located in the ECU flash and can not be modified by a
simple write access. All changes to the Reference Page must be done via Flash
programming.
The Working Page is located within the microcontroller's ED RAM. The Working
Page may be a portion of or the entire size of the ED RAM. The ED RAM used
for the emulation of calibration data must not be used by the ECU software
directly as general purpose RAM. It is recommended that the ED RAM is perma
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nently powered by the XETK or ECU. The XETK/INCA has the complete control
over the RAM used as Working Page and it's contents. When enabling data
emulation, the XETK establishes a basic start-up configuration of the data in
the Working Page by copying the corresponding data in the Flash to the emula
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tion space.
4.7.1
Page Switching
To enable calibration, the Working Page must be activated. The process of
switching from the Reference Page to the Working Page and vice versa is
known as page switching. The BR_XETK-S3.0 supports two methods of page
switching; however one method is only available for certain controllers.
The BR_XETK-S3.0 can access both the Reference Page and the Working Page,
regardless of which is active from the microcontroller's point of view and which
page switch method is used. The two types page switching methods are
described next.
4.7.1.1
Protocol Based Page Switching
The BR_XETK-S3.0 supports Protocol Based page switching for all supported
microcontrollers. Page switching is implemented in microcontroller software
by switching the overlay memory on (Working Page) and off (Reference Page)
using microcontroller overlay registers. The BR_XETK-S3.0 does not directly
control the microcontroller overlay registers. Instead, the BR_XETK-S3.0 and
microcontroller software use a simple communication method with a shared
mailbox in RAM. The XETK uses this mailbox to request and monitor page
NOTE
With serial ETKs such as the BR_XETK-S3.0, there is an important restriction
that no access to the memory is possible, while the ECU is not running. To
enable a cold start measurement (measurement during ECU power-up) in
spite of this restriction, the cold start measurement procedure is defined to
give the user the feeling of a parallel XETK. Please inquire further if you would
like additional details for the cold start measurement procedure.
