Epson E0C6001 Technical Manual page 91

E0C6001 TECHNICAL SOFTWARE
II-10
After an initial reset, the program counter page (PCP) is
initialized to 1H, and the program counter step (PCS), to
00H. This is why the program is executed from step 00H of
the first page.
The initial values of some internal registers and internal
data memory area locations are undefined after a reset. Set
them as necessary to the proper initial values in the pro-
gram.
The peripheral I/O functions (memory-mapped I/O) are
assigned to internal data memory area addresses 0E0H to
0FDH. Each address represents a 4-bit internal I/O register,
allowing access to the peripheral functions in 1-word (4-bit)
read/write units.