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GR716-DS-UM, May 2019, Version 1.29
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GR716
sponding ISR bit is not allowed to change value, and any received interrupt- / interrupt-acknowledge-
codes with that interrupt number are discarded.
33.5.2 Receiving interrupt- / interrupt-acknowledge-codes
When a control code with control flags set to “10” is received, and interrupt receive is enable (IR bit
in Interrupt distribution control register set to 1), the control code is considered an interrupt-code if bit
5 is 0, and an interrupt-acknowledge-code if bit 5 is 1. If an interrupt-code is received and the inter-
rupt number’s corresponding ISR bit is already set to 1, or an interrupt-acknowledge-code when the
ISR bit is 0, then the received interrupt- / interrupt-acknowledge-code is discarded without any further
action.
When an interrupt-code is received, and the corresponding ISR bit is 0, the ISR bit is set to 1. If the
interrupt number’s corresponding bit in the Interrupt tick-out mask register is set to 1 then the corre-
sponding bit in the Interrupt-code receive register is set to 1, the TICKOUT signal is asserted for one
clock cycle, and an AMBA interrupt is generated (if the IE bit in the Control register, and IQ bit in the
Interrupt distribution control register are both set to 1). If the interrupt number’s corresponding bit in
the Interrupt-code auto acknowledge mask register is set to 1, then an interrupt-acknowledge-code
will be automatically sent once the INT/ACK-timer has expired, and the ISR bit will be cleared again.
When an interrupt-acknowledge-code is received, and the corresponding ISR bit is 1, the ISR bit is set
to 0. If the interrupt number’s corresponding bit in the Interrupt tick-out mask register is set to 1, and
the interrupt-code that made the ISR bit get set to 1 in the first place was sent by software (through
register access), then the corresponding bit in the Interrupt-acknowledge-code receive register is set to
1. The TICKOUT signal is asserted for one clock cycle as well, and an AMBA interrupt is generated
(if the IE bit in the Control register, and IQ bit in the Interrupt distribution control register are both set
to 1).
Note that all received control codes, interrupt- / interrupt-acknowledge-codes or not, are outputted on
the TIMEOUT[7:0] signals, and the TICKOUTRAW signal is asserted for one clock cycle.
For more details regarding interrupt- / interrupt-acknowledge-code reception, please see the descrip-
tion of the interrupt distribution registers in section 33.11.
33.5.3 Transmitting interrupt- / interrupt-acknowledge-codes
Interrupt- / interrupt-acknowledge-codes can be transmitted either through the AMBA APB registers
or through the signals TICKINRAW, TIMEIN, and TICKINDONE.
To transmit an interrupt- / interrupt-acknowledge-code through the register interface the II bit in the
Interrupt distribution control register should be written to 1. When the bit is written the value of the
TXINT field determine which interrupt- / interrupt-acknowledge-code that will be sent.
To transmit an interrupt- / interrupt-acknowledge-code using the TICKINRAW signal the sender must
wait until TICKINDONE is low, then assert TICKINRAW and place the value of the interrupt- / inter-
rupt-acknowledge-code to be sent on the TIMEIN[7:0] signals. When TICKINDONE is asserted
again, the TICKINRAW signal should be de-asserted the same cycle.
Both methods of sending an interrupt- / interrupt-acknowledge-code requires that interrupt transmis-
sion is enabled (IT bit in Interrupt distribution control register set to 1). The actual sending of the
interrupt- / interrupt-acknowledge-code is delayed until the corresponding INT/ACK-timer has
expired.
For more details regarding interrupt- / interrupt-acknowledge-code transmission, please see the
description of the interrupt distribution registers in section 33.11.
33.5.4 Interrupt-code generation
Interrupt-codes can be generated automatically due to a number of internal events. Which events that
should force an interrupt-code to be sent, and what interrupt-number to use, is controlled from the