In the 8085 microprocessor, a hardware interrupt is a signal from an external device that temporarily halts the CPU's current operations to allow the device to communicate with the processor. A vector interrupt specifically refers to an interrupt that has a predefined memory address (vector) associated with it, which the processor jumps to when servicing the interrupt. For instance, the 8085 has several hardware interrupts, such as INTR, RST 7.5, RST 6.5, and RST 5.5, each with its own unique vector address, allowing for efficient and organized handling of multiple interrupt sources. This mechanism enables real-time processing and responsiveness to external events in embedded systems.
The 5.5 in RST 5.5 means that the interrupt vector is located between RST 5 and RST 6.
The TRAP interrupt is nomaskable in the 8085 microprocessor because TRAP is intended to indicate some serious system problem, or a hardware assisted debugger single step facility.
There are 2 types interrupts in 8085 such as: 1)hardware interrupt 2)software interrupt
The lowest priority interrupt in the 8085 microprocessor is INTR, unless you also consider the software interrupts, RST 0 through RST 7, which are even lower.
RST 5.5 is level triggered interrupt & maskable also. it can be masked by using SIM intrruction. Vector address of the RST 5.5 interrupt is 002Ch
In the 8086/8088, the interrupt vector table is the first 1024 bytes of memory. In the 8085, the interrupt vector table is the first 64 bytes of memory if using the RST form of interrupt, otherwise the interrupt vector is provided by the interrupting device, usually in the form of a CALL instruction. The interrupt handler is wherever the interrupt vector points to.
RSTn(0-7) is software interrupt & RST(7.5,6.5,5.5) are INTEL's 8085 maskable interrupts their priority is respectively 7.5,6.5,5.5.RSTn.5 is hardware intterrupt and it is controlled by the external pin available on the chip of 8085. it is used to interrupt the microprocessor from its normal execution and tends to execute some ISR(interrupt service routine)
The name, RST6.5, was chosen because the interrupt vector lies halfway between RST 6 and RST 7, specifically at address 0034H.
The hardware initiates an interrupt when it feels that the situation requires the CPU's action.
RIM is Read Interrupt Mask. It is used to access the interrupt mask register, which contains the status of the three interrupt masks and the serial input data pin.
8085 is a microprocessor designed by Intel
when interrupts requests arrive from two or more devices simultaneously , the process has to decide which request should be serviced first and which one should delayed. the processor takes the decision with the help of interrupt priorities.