eorex
EU1010
Memory
The EU1010 has a 14-bit program counter which can totally address 16K x 8 bits. All the special function
registers, data RAM, stack RAM and program ROM are assigned in this area as the following diagram.
0000H
Special Function Register
0022H
Un-used
00A0H
( zero page )
Data RAM : 96 x 8 bits
00FFH
0100H
Data & Stack RAM : 32 x 8 bits
Un-used
011FH
2000H
2FFFH
Program ROM : 4K x 8 bits
Figure_A Memory mapping diagram
Program ROM
The EU1010 contains 4Kx8 bit program OTP and its addressing size is assigned from $2000H to
$2FFFH. After power on reset, the data restored in addresses $2FFCH and $2FFDH are loaded into
program counter. It means that RESET vector address is located in $2FFCH and $2FFDH.
Data RAM and STACK RAM
The EU1010 data RAM are located from $A0H to $11FH. All the data RAM area from $A0H to $0FFH
could be accessed by zero-page addressing mode. That STACK RAM could be accessed from $100H to
$11FH. Actually, the area of $100H ~ $11FH, could be accessed as data RAM or STACK RAM. User
needs to preset stack pointer (SP) after power on reset. Program Counter (PC) should be initialized after
power on reset that ROM address $2FFCH and $2FFDH content will be loaded into Program Counter.
Feb.2009
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EOREX [ EOREX CORPORATION ]
