AN3044

ECU level diagnostic

Doc ID 16196 Rev 2

7/20

2

ECU level diagnostic

ECU level diagnostic does not usually allow access to the JTAG pins. The ECU level

diagnostic is describing diagnostic possibilities with only the pins involved for serial boot

(i.e.: without using JTAG pins).

2.1

SPC563Mx and SPC564Ax traceability information

Each SPC56x has traceability information stored inside the Flash (shadow Flash).

The traceability information is stored in memory locations that are accessible by the

application software so that user application software can be used to read them and send

them over the selected diagnostic communication interface, UART,LIN, CAN or FlexRay.

To send the traceability information, users can use a user defined diagnostic mode that is

entered by the application software or use a serial boot mode. This is mainly driven by the

password strategy of the OEM.

Case1: using a user defined diagnostic mode

When the Flash is protected, the application software can always read the traceability

information. The application software may have then specific diagnostic mode that allows to

send this information over a predefined communication interface (CAN, LIN, K-line,

FlexRay). This operation does not require people to know the Flash password to do this in

the field.

Case2: using a serial boot mode and by allowing users to know the password

The traceability information stored inside SPC56x can be read by an external tool using the

password defined by users.

Case3: using a serial boot mode and avoiding users to know the password

To allow to read traceability information using the serial links only, the following procedure

must be implemented:

●

Reserve locations in the RAM (preferably with highest addresses)

●

Use the application software to make systematically a copy of the locations in the Flash

to selected locations in the RAM during the power on procedure

●

Start the ECU in application mode first

●

Apply then a reset without supply shutdown and ensure the MCU is brought in serial

boot mode

●

Use the software uploaded in RAM to export the traceability information using the

selected serial link

In this mode (i.e.: serial boot control word is not 0x55AA and censor control word is not

0x55AA), the Flash is not enabled in boot mode and external JTAG pins do not allow direct

access to the device when the Flash is enabled.

2.2

ECU self tests

ECU level self tests can be run either from the application software (ex: selection from ECU

pins) or from the microcontroller RAM.