TMP91C824
91C824-49
2008-02-20
(2)
External interrupt control
Symbol
Name
Address
7 6 5 4 3 2 1 0
−
−
I3EDGE
I2EDGE
I1EDGE
I0EDGE I0LE NMIREE
W
0 0 0 0 0 0 0 0
IIMC
Interrupt
input
mode
control
8CH
(Prohibit
RMW)
Always
write 0
Always
write 0
INT3EDGE
0: Rising
1: Falling
INT2EDGE
0: Rising
1: Falling
INT1EDGE
0: Rising
1: Falling
INT0EDGE
0: Rising
1: Falling
INT0 mode
0: Edge
1: Level
1: Operates
even on
rising/
falling
edge of
NMI
INT0 level enable
0 edge
detect
INT
1
H level INT
NMI
rising edge enable
0
INT request generation at falling edge
1
INT request generation at rising/falling edge
(3)
Interrupt request flag clear register
The interrupt request flag is cleared by writing the appropriate micro DMA start
vector, as given in Table 3.4.1, to the register INTCLR.
For example, to clear the interrupt flag INT0, perform the following register
operation after execution of the DI instruction.
INTCLR
←
0AH: Clears interrupt request flag INT0.
Symbol
Name
Address
7 6 5 4 3 2 1 0
CLRV5 CLRV4 CLRV3 CLRV2 CLRV1 CLRV0
W
0 0 0 0 0 0
INTCLR
Interrupt
clear
control
88H
(Prohibit
RMW)
Interrupt
vector
(4)
Micro DMA start vector registers
This register assigns micro DMA processing to which interrupt source. The
interrupt source with a micro DMA start vector that matches the vector set in this
register is assigned as the micro DMA start source.
When the micro DMA transfer counter value reaches zero, the micro DMA transfer
end interrupt corresponding to the channel is sent to the interrupt controller, the
micro DMA start vector register is cleared, and the micro DMA start source for the
channel is cleared. Therefore, to continue micro DMA processing, set the micro DMA
start vector register again during the processing of the micro DMA transfer end
interrupt.
If the same vector is set in the micro DMA start vector registers of more than one
channel, the channel with the lowest number has a higher priority.
Accordingly, if the same vector is set in the micro DMA start vector registers of two
channels, the interrupt generated in the channel with the lower number is executed
until micro DMA transfer is complete. If the micro DMA start vector for this channel
is not set again, the next micro DMA is started for the channel with the higher
number (Micro DMA chaining).