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21 | Hardware Description
3.6
Data Emulation and Data Measurement
The BR_XETK-S1.0 is a serial XETK using DAP as the primary microcontroller inter-
face. Typical of all serial (X)ETKs, the RAM used for data emulation and data mea-
surement 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 cannot be modified by a simple
write access. All changes to the Reference Page must be done via Flash program-
ming.
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 permanently 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 estab-
lishes a basic start-up configuration of the data in the Working Page by copying
the corresponding data in the Flash to the emulation space.
NOTE
With serial ETKs such as the BR_XETK-S1.0, 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.
3.6.1
Page Switching
To enable calibration, the Working Page must be activated. The process of switch-
ing from the Reference Page to the Working Page and vice versa is known as page
switching. The BR_XETK-S1.0 supports two methods of page switching; however
one method is only available for certain controllers.
The BR_XETK-S1.0 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 of page switching methods are
described next.
3.6.1.1
Protocol Based Page Switching
The BR_XETK-S1.0 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-S1.0 does not directly control the
microcontroller overlay registers. Instead, the BR_XETK-S1.0 and microcontroller
software use a simple communication method with a shared mailbox in RAM. The
ETAS BR_XETK-S1.0 | User Guide
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