For the specific chip I used (MSP430FR2355), you could read and execute code at max 8MHz without wait states. Which means it's reading at most 4MHz since each M

For the specific chip I used (MSP430FR2355), you could read and execute code at max 8MHz without wait states. Which means it's reading at most 4MHz since each MSP430 instruction that accesses memory requires at least 2 cycles. So latency is at least 1/4MHz=0.25µs