IPC@CHIP Documentation - SC12 @CHIP-RTOS V1.10

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Using Hardware API
1. The HAL functions keep interrupts disabled, so you can call them inside an interrupt routine. The
PFE functions are only for choosing and initializing a specific function on the selected pin. They
should be called once in your application for initializing your hardware environment and not at
runtime or inside interrupt routines.
2. Do not use functions of the RTOS API inside of a normal HW API user ISR. For this purpose
install a RTX user ISR, see Install ISR.
3. The latency time of the user ISR (from generation of an interrupt until first line of code inside the
user ISR) depends on the used IPC@CHIP, see Performance comparision .
4. Instead of HAL functions Read data bus and Write data bus you can call C-functions inportb
and outportb from DOS.H for faster data bus accesses.
5. Usage of DMA0/INT5 and DMA1/INT6:
DMA0 and INT5 are served inside the @CHIP-RTOS with a single shared interrupt handler.
(Likewise for DMA1 and INT6.)
If an user application has activated serial EXT DMA mode and also wants to use external
interrupt INT5, the DMA interrupt event is higher priority. (And again, likewise for COM DMA
mode and INT6.)
This means that if a DMA0/1 interrupt occurs simultaneous with an external INT5/6 interrupt, the
installed user handler for the external interrupt is not called.
See Hardware API
6. Usage of NMI/Power fail detection:
The NMI function of the multifunction pin 17 (RESET/NMI/LINK_LED) of the IPC@CHIP
SC11/SC12/SC13 is for power fail purposes only. It is not possible to use NMI as a "normal"
interrupt pin like e.g. INT0 for generating interrupts. It can only be used as described in the
IPC@CHIP hardware documentation.
The flowchart below describes how the @CHIP-RTOS handles an incoming NMI interrupt.
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