SM8521 datasheet(14/56 Pages) SHARP

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SM8521

Data Format

The SM85CPU supports four data types : bit, 4-bit

BCD, byte, and word data.

The register file (0000H-007FH) and RAM (0080H-

00FFH) accessible with register file R and register

file pair RR addressing support processing for all 4

data types : bit, 4-bit BCD, byte, and word data.

Fig. 3 shows the data layout in the register file.

• Bit data (register file)

Bit manipulation instructions access bit data in the

the byte address in the register file (0000H-007FH),

or RAM (0080H-00FFH), and the operand b, which

gives the bit number within the byte.

• Byte data (register file)

Instructions access the byte data in the register file

by register file R addressing, which gives the byte

data address in the register file (0000H-007FH) or

RAM (0080H-00FFH).

• Word data (register file)

Instructions access word data in the register file by

address, even and 2 bytes address, in the register

file (0000H-007FH) or RAM (0080H-00FFH). The

address must be even (0, 2, 4,…, 254). Specifying an

odd address leads to unreliable results.

• BCD data (register file)

The decimal adjust instruction (DA), used to adjust

BCD digits after an odd or subtraction, accesses a

BCD data byte in the register file by register file R

addressing.

• Notice for the general register on register file

The general registers are the first 16 bytes (0000H-

000FH) in the register file. They can be accessed

as byte-sized by register file R addressing and as

word-sized by register file pair RR addressing.

MEMORY DATA FORMATS

The memory area (ROM and RAM 0000H-FFFFH)

supports processing for all 4 data types : bit, 4-bit

BCD, byte and word data. However, bit data is

limited to the ranges (0000H-00FFH, FF00H-FFFFH),

and 4-bit BCD data to the ranges 0000H-00FFH.

Fig. 3 shows the data layout in memory.

• Bit data (memory)

Bit manipulation instructions access bit data in

memory by register index n(r) addressing, which

gives the byte address in the range (0000H-00FFH),

or by direct special page DAp addressing, which

gives the byte address in the range (FF00H-FFFFH),

and the operand b, which gives the bit number

within the byte.

• Byte data (memory)

Instructions access the byte data in memory by

shorthand (0000H-00FFH or FF00H-FFFFH) or full

(0000H-FFFFH) address.

• Word data (memory)

Instructions access the word data, continue 2

bytes, in memory by shorthand (0000H-00FFH or

FF00H-FFFFH) or full (0000H-FFFFH) address.

Unlike word data in the register file, the address

can be even or odd.

• BCD data (memory)

The decimal adjust instruction (DA), used to adjust

BCD digits after an odd or subtraction, accesses a

BCD data byte in memory by register index @r

addressing.

• Notice for general register on memory

The general registers are actually in a RAM area

specified by register pointer RP, so they can be

read

and

modify

directly

RAM.

While

programming, the programmer must take care to

arrange

program

data

that

other

RAM

operations do not destroy general registers content.

SM8521 Datasheet(PDF) 14 Page - Sharp Corporation

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