Computer Hardware User's Manual

TMP92CM22
2007-02-16
92CM22-45
(4) 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
F8H
(Prohibit
RMW)
Interrupt clear
(5) 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 “0”, 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 completed. 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).