LSI 53C810A - Manual (Page 118)

5-44 Operating Registers
Register: 0x39 (0xB9)
DMA Interrupt Enable (DIEN)
Read/Write
This register contains the interrupt mask bits corresponding to the
interrupting conditions described in the
DMA Status (DSTAT) register. An
interrupt is masked by clearing the appropriate mask bit. Masking an
interrupt prevents IRQ/ from being asserted for the corresponding
interrupt, but the status bit is still set in the
DMA Status (DSTAT) register.
Masking an interrupt does not prevent setting the ISTAT DIP. All DMA
interrupts are considered fatal, therefore SCRIPTS stops running when
a DMA interrupt occurs, whether or not the interrupt is masked. Setting
a mask bit enables the assertion of IRQ/ for the corresponding interrupt.
(A masked nonfatal interrupt does not prevent unmasked or fatal
interrupts from getting through; interrupt stacking begins when either the
Interrupt Status (ISTAT) SIP or DIP bit is set.)
The IRQ/ output is latched. Once asserted, it will remain asserted until
the interrupt is cleared by reading the appropriate status register.
Masking an interrupt after the IRQ/ output is asserted does not cause
deassertion of IRQ/.
For more information on interrupts, see Chapter 2, “Functional
Description.”
R Reserved 7
MDPE Master Data Parity Error 6
BF Bus Fault 5
ABRT Aborted 4
SSI Single Step Interrupt 3
SIR SCRIPTS Interrupt Instruction Received 2
R Reserved 1
IID Illegal Instruction Detected 0
7 6 5 4 3 2 1 0
R MDPE BF ABRT SSI SIR R IID
x 0 0 0 0 0 x 0