Mapping Of Registers; Indexed Mapping; Direct Mapping - Epson S1D13503 Series Technical Manual

EPSON

5.3 Mapping of Registers

The S1D13503 has an internal set of 16-/8-bit read/write registers which configure it for various
modes of operation. The registers can be accessed in two ways; Indexed Addressing and Direct
Addressing.
Note: Refer to the S1D13503 Hardware Functional Specification for more information on the S1D13503
registers.

Indexed Mapping

This method requires only two sequential I/O address locations starting from the base I/O address.
The base I/O address is determined by the power-on state of the SRAM data lines VD[4 through 12].
See "Summary of Configuration Options" in the S1D13503 Hardware Functional Specification.
The S5U13503P00C Evaluation Board uses three sequential I/O addresses which are defined as
Index Address, Index Data, and Memory Banking. To access registers using this method, an Index
Address must be written to the first I/O address location allowing data to be written/read to/from the
second I/O address.
The Memory Banking port is specific to the S5U13503P00C implementation and is used to select
one of two 64K display memory banks; a read from this port selects bank 0, and a write to this port
selects bank 1. Note that the values read from or written to the Memory Banking port are not impor-
tant.
Example 14
Write 12h to register 08h on the S5U13503P00C evaluation board; the base port
address is 310h, and indexed port mapping is used.
1. Write 08h to the index register
The index register is at base port address + 0 = 310h.
MOV DX,310h
MOV AL,08h
OUT DX,AL
2. Write 12h to the data register
The data register is at base port address + 1 = 311h.
MOV DX,311h
MOV AL,12h
OUT DX,AL

Direct Mapping

This method of addressing requires 16 sequential I/O addresses starting from the base I/O address.
The base I/O address is determined by the power-on state of the SRAM data lines VD[7 through 12].
See "Summary of Configuration Options" in the S1D13503 Hardware Functional Specification.
To access the internal 16 registers of the S1D13503, simply perform I/O read/write functions to the
absolute address as defined in the previous paragraph.
There is no memory banking available in direct addressing mode.
Example 15
Write 12h to register 08h on the S5U13503P00C evaluation board; the base port
address is 310h, and direct port mapping is used.
1. Calculate the port address for register 08h.
2. Write the value 12h to port address 318h.
MOV DX,318h
MOV AL,12h
OUT DX,AL
2-30
Port address = 310h + 8h = 318h
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