> Is the 6507 identical with the 6502 from an opcode perspective? Yes, I believe so. The differences were in the packaging - simplified to lower costs. "The

> Is the 6507 identical with the 6502 from an opcode perspective? Yes, I believe so. The differences were in the packaging - simplified to lower costs. "The main differences between 6502 and 6507 is that the 6507 has less address lines so it can only address 8K instead of 64K and it also lacks the IRQ# and NMI# interrupt lines." https://forums.atariage.com/topic/199454-programming-asm-for-6502-vs-6507-questions/ https://forums.atariage.com/topic/199454-programming-asm-for... But I found this bit from the NESDev wiki I linked above very interesting: "Most NMOS 6502 cores interpret them the same way, although there are slight differences with the less stable instructions. CMOS variants of the 6502 handle them completely differently, and later CPUs in the same family (e.g. 65C02, HuC6280, 65C816) were free to implement new instructions in the place of the unused ones."