RX610 Group
10. ICU
R01UH0032EJ0120 Rev.1.20
Page 246 of 1006
Feb 20, 2013
10.4.3
Selecting Interrupt Request Destinations
Sources that can act as interrupts or activate the DTC and DMAC have ISEL[1:0] bits in the corresponding ISELRi for
setting the destination of interrupt requests. The selectable destinations for each of the interrupt sources are fixed and
they are listed in table 10.4, Interrupt Vector Table. Do not select a destination which is not indicated in the table.
The following four types of request-destination settings for the ISEL[1:0] bits in ISELRi are available.
1. Interrupt request for the CPU
2. Activate the DTC and convey the interrupt request to the CPU on completion of data transfer.
3. Request to activate the DMAC
4. Activate the DMAC and then convey the interrupt request to the CPU (without waiting for the completion of DMA
transfer).
If the source is to activate the DTC or DMAC, use edge detection of the interrupt.
For most interrupts from peripheral modules, only edge detection is available.
If edge detection is to be used for an external interrupt, make the setting for edge detection in the IRQMD[1:0] bits in
IRQCRn.
If the setting of the ISEL[1:0] bits in ISELRi is 00b, the interrupt control unit conveys interrupt requests to the CPU.
If the setting of the ISEL[1:0] bits in ISELRi is 01b, the interrupt control unit conveys an activation request to the DTC.
Further operation is as follows, according to the setting of the DISEL bit in MRB of the DTC.
•
When the DISEL bit in MRB of the DTC is set to 0, the DTC performs the specified number of data transfers. The
value of the ISEL[1:0] bits in ISELRi is kept at 01b until the transfer counter reaches 0. On completion of data
transfer (i.e. when the transfer counter reaches 0), the ISEL[1:0] bits are automatically updated to 00b. At this point,
the interrupt control unit conveys the interrupt request to the CPU.
•
When the DISEL bit in MRB of the DTC is set to 1, the ISEL[1:0] bits in ISELRi are automatically updated to 00b
on completion of an individual data transfer, regardless of the transfer counter. At this point, the interrupt control unit
conveys the interrupt request to the CPU.
In cases where the ISEL[1:0] bits in ISELRi are to be re-set to 01b after having been updated to 00b, modify the value of
the bits within the corresponding interrupt exception handler. Furthermore, if re-activation of the DTC is required, ensure
that generation of the interrupt signal is possible after setting the ISEL[1:0] bits in ISELRi to 01b.
If the setting of the ISEL[1:0] bits in ISELRi is 10b, the interrupt control unit conveys an activation request to the
DMAC.
After DMAC activation, the value of the ISEL[1:0] bits in ISELRi is kept at 10b.
When the selected form of DMA transfer is consecutive-operand transfer or the same interrupt source activates multiple
channels, regardless of the type of DMA transfer, enable the generation of further interrupts with the timing described
below.
•
When the form of DMA transfer is consecutive-operand transfer, make settings to enable the generation of a next
interrupt by the source on completion of all DMA transfer on activated channels.
*1
•
When the same interrupt source activates multiple channels, regardless of the type of DMA transfer, make settings to
enable the generation of a next interrupt by the source on completion of transfer on all channels.
*2