MSM80C154S/83C154S/85C154HVS

3.3 EA (CPU Memory Separate)

3.3.1 Outline

The function of the EA pin is to determine whether a CPU internal program memory (ROM) instruction or an external program instruction is to be executed.

(1)Internal ROM mode

If the EA pin is connected to VCC and a “1” reset signal is applied to the RESET pin to reset the CPU, an internal program memory (ROM) is executed from address 0. (MSM83C154S, MSM85C154HVS)

(2)External ROM mode

If the EA pin is connected to VSS and a “1” reset signal is applied to the RESET pin to reset the CPU, an external program memory is executed from address 0.

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Sonic Alert msm85c154hvs, msm83c154s, msm80154s user manual EA CPU Memory Separate, MSM80C154S/83C154S/85C154HVS