Fujitsu FR60 Hardware Manual page 356

CHAPTER 9 INTERRUPT CONTROLLER
■ Return from Standby Mode (Sleep/Stop)
This module implements a function that causes a return from stop mode if an interrupt request occurs. If at
least one interrupt request that includes NMI occurs (with an interrupt level other than 11111) from the
peripheral, a return request from stop mode is generated for the clock controller.
Since the priority decision unit restarts operation when a clock is supplied after returning from stop, the
CPU executes instructions until the result of the priority decision unit is obtained.
The same operation occurs after a return from the sleep state.
Registers in this module can be accessed even in the sleep state.
Notes:
• The device returns from stop mode if an NMI request is issued. However, set an NMI so that valid
input can be detected in the stop state.
• Provide an interrupt level of 11111 in the corresponding peripheral control register for an interrupt
source that you do not want to cause return from stop or sleep. (5) Clearing an interrupt source.
■ Example of Using the Hold Request Cancellation Request Function (HRCR)
To allow the CPU to perform high-priority processing during DMA transfer, cancel a hold request for
DMA and clear the hold state. In this example, an interrupt is used to cancel a hold request to the DMA,
allowing the CPU to perform priority operations.
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Control registers
1. Hold request cancellation level setting register (HRCL): This module
If an interrupt with a higher interrupt level than the level defined in this register occurs, a hold request
cancellation request is issued to DMA. This register sets the level to be used as the criterion for this
purpose.
2. ICR: This module
This register sets a higher level than the level in the HRCL register for the ICR corresponding to the
interrupt source that will be used.
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Hardware configuration
Figure 9.3-1 shows the flow of the signals that are related to the hold request.
This module
IRQ MHALTI
I-UNIT
(ICR)
(HRCL)
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Figure 9.3-1 Flow of Signals Related to Hold Request
Bus access request
DMA B-UNIT
DHREQ: D bus hold request
DHREQ
CPU DHACK: D bus hold acknowledge
IRQ: Interrupt request
MHALTI: Hold request
DHACK
cancellation request