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If in this way a NMI request or (maskable) IRQ is detected the B flag is set to zero and causes the processor to execute the BRK instruction next instead of executing the next instruction based on the program counter. [84] [85] The BRK instruction then pushes the processor status onto the stack, with the B flag bit set to zero.
The most significant byte (MSB) of the aborted instruction's address is pushed onto the stack. The least significant byte (LSB) of the aborted instruction's address is pushed onto the stack. The status register is pushed onto the stack. The interrupt disable flag is set in the status register. PB is loaded with $00.
This is set to zero on startup or reset, meaning that its store-Z-to-memory instruction, STZ, works just like it does in the 65C02 where the same instruction means store-zero-to-memory. This allows unmodified 65C02 code to run on the 65CE02. A number of other instructions are added or modified to allow access to the Z register.
The primary change from the 6502 is the addition of an 8-bit general purpose I/O port, although 6 I/O pins are available in the most common version of the 6510. In addition, the address bus can be made tristate and the CPU can be halted cleanly.
The Western Design Center (WDC) 65C02 microprocessor is an enhanced CMOS version of the popular nMOS-based 8-bit MOS Technology 6502.It uses less power than the original 6502, fixes several problems, and adds new instructions.
The Mitsubishi 740 family has a processor core that executes a superset of the 6502 instruction set including many of the extensions added in the 65C02. There is a core set of new instructions common across all 740 family members, plus other instructions that exist in specific parts.
The 6507 uses a 28-pin configuration, with 13 address pins (A0..A12) and 8 data pins (D0..D7). The seven remaining pins are used for power (Vss, Vcc), the CPU timing clock (φ0, φ2), to reset the CPU (the /RES pin), to request a CPU wait state during its next memory read access (the RDY pin), and for the CPU to indicate if a read or write memory (or MMIO device) access is being performed (the ...
The HuC6280 contains a 65C02 core which has several additional instructions and a few internal peripheral functions such as an interrupt controller, a memory management unit, a timer, an 8-bit parallel I/O port, and a programmable sound generator (PSG). The processor operates at two speeds, 1.79 MHz and 7.16 MHz.