Sundance SMT335E - Manual (Page 12)

Version 1.5 Page 12 of 53 SMT335E SMT375E User Manual
Interrupts
The generation of a CPU interrupt by a comm-port, an SDB, or the Global Bus starts
when the FPGA asserts an interrupt condition. For example, this may be the result of
an input FIFO becoming not empty or an output FIFO not full.
The interrupt condition is then further controlled by interrupt condition enables in the
FPGA. If enabled, an asserted interrupt condition will cause one of the CPU’s
external interrupt lines to be asserted and an interrupt event to be latched in the
processor’s Interrupt Flag Register (IFR).
Finally, the processor will be interrupted, providing the interrupt event is enabled in
the processor’s Interrupt Enable Register (IER) and the Global Interrupt Enable (GIE)
is set in the processor’s Control and Status Register (CSR).
The C6000 provides four external interrupt input lines, EXT_INT4, EXT_INT5,
EXT_INT6, and EXT_INT7, which can be driven by a variety of interrupt conditions.
Each external interrupt has a separate interrupt control register (INTCTRLn) where
you set bits to enable the interrupt condition.
Interrupt Control Register
INTCTRL4 0x03E00000
INTCTRL5 0x03E80000
INTCTRL6 0x03F00000
INTCTRL7 0x03F80000
31–30 29–28 27–26 25–24 23–22 21–20 19–18 17–16
CP0 IE CP1 IE CP2 IE CP3 IE CP4 IE CP5 IE SDBA IE SDBB IE
RW,00 RW,00 RW,00 RW,00 RW,00 RW,00 RW,00 RW,00
15 14 13 12 11 10
GB IE TCLK1 IE TCLK0 IE IIOF2 IE IIOF1 IE IIOF0 IE
RW,0 RW,0 RW,0 RW,0 RW,0 RW,0
9–0
RW,0000000000
Field Description Interrupt condition selected