KIT_TC1797_SK Infineon Technologies, KIT_TC1797_SK Datasheet - Page 26

• Manufacturer Part Number: KIT_TC1797_SK
• Description: KIT STARTER AUDO FUTURE TC1797
• Manufacturer: Infineon Technologies
• Series: Audo Futurer
• Type: MCUr

Specifications of KIT_TC1797_SK

• Contents: Board, Adapters, Cables, CD, Power Supply
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: TC1797
• Other names: KITTC1797SKIN

typically non-privileged. Unfortunately, with this issue that premise no longer
holds - the code interrupted and state saved in a CSA can be that of a privileged
trap handler. Dealing with this changed circumstance is easy, provided it is
considered whenever CSA's are examined or manipulated.
Workaround
As described previously, the main problem associated with this erratum is the
delay that may be incurred before the servicing of certain critical trap types,
such as NMI, if no additional action is taken. If this is an issue for a system, then
in order to minimize the impact of this erratum it is necessary to adapt the
interrupt handlers to check for the occurrence of this issue and react
accordingly.
The occurrence of this issue may be checked for by one of two methods,
dependent upon whether all trap classes or just a limited set are considered
timing critical.
If it is required to check for the occurrence of this issue for all trap classes, then
this may be performed by checking the value of the PCXI.PIE register bit within
the interrupt handlers, before any further context operations (such as BISR) are
performed. If PCXI.PIE is clear, such that no interrupt should have been taken,
then this indicates the occurrence of this issue. Although when this method is
used then it is preferred to check the value of PCXI.PIE before any further
context operations are performed, it is possible to use this method after
additional context operations have been performed. In this case it is necessary
to traverse the CSA list to check the required PCXI.PIE value from the
appropriate saved context.
If it is necessary within a system to check for the occurrence of this issue just
for specific, timing critical, trap classes, then this may be performed by
examination of the return address, held in the A11 register, within the interrupt
handler and comparing this return address against the trap vector address(es).
For example, if only the NMI trap is a system issue requiring immediate action,
the following code may be added to the interrupt handler to determine if the
interrupt was taken at the start of the NMI handler:
TC1797, EES-AC, ES-AC, AC
...
< Timing critical section of Interrupt Handler >
movh.a a12, #@his(NMITrapAddress)
26/101
; BTV OR 0xE0
Functional Deviations
Rel. 1.3, 18.12.2009
Errata Sheet