TMP47C101 datasheet(5/32 Pages) TOSHIBA

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TMP47C101/201

2.2 Program Memory (ROM)

Programs and ﬁxed data are stored in the program memory.

The instruction to be executed next is read from the address

indicated by the contents of the PC.

The fixed data can be read by using the table look-up in-

structions.

• Table look-up instructions

[LDL A, @DC], [LDH A, @DC+]

The table look-up instructions read the lower and

upper 4 bits of the ﬁxed data stored at the address

speciﬁed in the data counter (DC) to place them into

the accumulator. [LDL A, @DC] instruction reads the

lower 4 bits of ﬁxed data, and [LDH A, @DC+] instruc-

tion reads the upper 4 bits.

The DC is a 12-bit register, allowing it to address the

entire program memory space.

Example: When [LDL A, @DC] instruction is executed

with the DC value being 7AOH being 58H,

“8” is stored in the accumulator; when [LDH

A, @DC+] instruction is executed, “5” is

stored in the accumulator and the DC value

is incremented to 7A1H.

Figure 2-2. Conﬁguration of Program Memory

2.2.1 Program Memory Capacity

The 47C101 has 1024 x 8 bits (addresses 000H through 3FFH)

of program memory (mask ROM), the 47C201 has 2048 x 8

bits (addresses 000H through 7FFH).

2.2.2 Program Memory Map

Figure 2-3 shows the program memory map. Address 000H -

086H of the program memory are also used for special pur-

poses. On the 47C101, no physical program memory exists in

the address range 400H through 7FFH. However, if this space

is accessed by program, the most signiﬁcant bit of each

address is always regarded as “0” and the contents of the pro-

gram memory corresponding to the address is always

regarded as “0” and the contents of the program memory cor-

responding to the address 000H through 3FFH are read.

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