This pragma allows to control the technique used for stack allocation in functions. The default technique is to use a fast stack allocation. However, this technique cannot be used when the function is called from an Interrupt Service Routine (ISR), so it must be manually disabled in this specific case5
(ie: #pragma fast_stack 0
). The standard technique must be re-enabled after the concerned function (ie: #pragma fast_stack 1
).
Note that:
#pragma fast_stack 1