According to SATTECH 28 (Using dual CPUs on the Sega Saturn), slave CPU interrupts are not set from the SCU, but are connected from a peripheral module called DCC, which controls dual CPU operation.
Interrupts used by the slave CPU:
Internal peripheral modules (6 of them, including FRT)
H-blank-in (source IRL2, vector 0x41)
V-blank-in (source IRL6, vector 0x43)
Unlike master CPU, the slave CPU does not have an SR mask restriction. To mask interrupts, use the SR mask.
H-blank-in interrupts and V-blank-in interrupts:
In the slave CPU, both the H-blank-in and V-blank-in interrupts are level signal interrupts that accept interrupts during the blank period. For example, when V-blank-in interrupt processing begins and ends, the interrupt is restarted as long as the V-blank period continues.
According to SATTECH 28 (Using dual CPUs on the Sega Saturn), slave CPU interrupts are not set from the SCU, but are connected from a peripheral module called DCC, which controls dual CPU operation.
Interrupts used by the slave CPU:
Unlike master CPU, the slave CPU does not have an SR mask restriction. To mask interrupts, use the SR mask.
H-blank-in interrupts and V-blank-in interrupts:
In the slave CPU, both the H-blank-in and V-blank-in interrupts are level signal interrupts that accept interrupts during the blank period. For example, when V-blank-in interrupt processing begins and ends, the interrupt is restarted as long as the V-blank period continues.