RTE-V852-PC
USER’ S MANUAL (Rev. 1.10)
42
•
NMI request from JROMEM: NMI is generated by the input to the NMI pin of the JROMEM
connector on the Base board. See Section 3.19 for details.
•
Request received from ISA bus: NMI can be used for controlling communications via the ISA
bus. This NMI is used when the Multi debugger is connected through the ISA bus.
•
Request by NMI_SW: NMI is generated when the NMI switch (NMI_SW) on the Socket board is
pressed.
It is possible to mask the NMI by means of hardware. See Sections 6.8 and 6.10 for an explanation
of the masking method.
The following procedure must be applied when an NMI occurs.
À
Mask the NMI by means of hardware by setting NMIMASK of the NMI mask port to “ 1” .
Á
Determine the NMI request source. This can be identified at the NMI status port (see Section
6.9).
Â
Clear the request by performing NMI processing for the request source.
Ã
Reset the mask by setting NMIMASK of the NMI mask port to “ 0” .
Ä
Return from NMI processing.
The figure below outlines the NMI generation logic.
UART1_NMIEN
To CPU
NMI-
BASE_NMI-
NMI_MASK
From SW_NMI
From JROM_EM
SW_NMI-
ROM_EMLT_NMI-
UART1_NMI
UART2_NMIEN
UART2_NMI
PRT_NMIEN
PRT_NMI
ISACOM_NMIEN
ISACOM_NMI
EXTBUS_NMIE
N
EXTBUS_NMI
TOVER_NMIEN
TOVER_NMI
TIMER_NMIEN
TIMER_NMI