Hallo,

i have a Oki 83C154 MPU wich surely is connected to an external EPROM from which the Main Programm is loaded. The Program in the internal ROM is disabled (i think so because only external program is running)

#1 Q: Is it right that in this configuration the internal ROM is completly hided so that i can's access it any more?

The MPU also seems to be connected to a Chip (i think it is an external RAM - but i'am not sure)

In the program code you have the MOV and the MOVX command to access data. Now i have the problem that i am not sure what type of ROM/RAM the program access when there is i.e. a MOVX A, DPTR (DPTR=3DEFh) or MOVX A, DPTR (DPTR=15AAh)

in the first example i think it accesses the External Programm EPROM because on this location in the EPROM are Tables the program uses. In the second example i'am absolutly not sure because at adr. 15AAh normaly in the Program EPROM is program code so it make no sense to read a byte from the program code.

#2 Q: How can i see in the asm. sourcecode on what type of RAM/ROM the MPU accesses?

#3 Q: Is there a memory map i.e. from adr. x to adr. y = External EPROM and from adr. a to adr. b is External RAM and so on?

#4 Q: Is it possible to access external and internal RAM when an external RAM is connected or is it like the program ROM, that if you connect an external ROM the internal ROM is disabled and hided?

Hope anyone can answer me these questions because the datasheets don't help me.

Thanks
Malte S.