7548 Просмотр технического описания (PDF) - Renesas Electronics

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7548

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

Renesas Electronics 

7548 Group

Memory

• Special Function Register (SFR) Area

The SFR area in the zero page contains control registers such as

I/O ports and timers.

• RAM

RAM is used for data storage and for a stack area of subroutine

calls and interrupts.

• ROM

The first 128 bytes and the last 2 bytes of ROM are reserved for

device testing and the rest is a user area for storing programs.

The user area includes the function set ROM area.

• Interrupt Vector Area

The interrupt vector area contains reset and interrupt vectors.

• Zero Page

The 256 bytes from addresses 000016 to 00FF16 are called the

zero page area. The internal RAM and the special function

registers (SFR) are allocated to this area.

The zero page addressing mode can be used to specify memory

and register addresses in the zero page area. Access to this area

with only 2 bytes is possible in the zero page addressing mode.

• Special Page

The 256 bytes from addresses FF0016 to FFFF16 are called the

special page area. The special page addressing mode can be used

to specify memory addresses in the special page area. Access to

this area with only 2 bytes is possible in the special page

addressing mode.

[ROM code protect]

Address FFDB16 of QzROM version is ROM code protect

address and cannot be used for programming. “0016” is written

into this address when selecting the protect bit write by using a

serial programmer and selecting protect enabled for writing

shipment by Renesas Technology corp.. When “0016” is set to

the ROM code protect address, the protect function is enabled, so

that reading or writing from/to the corresponding area is disabled

by a serial programmer.

As for the QzROM product in blank, the ROM code is protected by

selecting the protect bit write at ROM writing with a serial programmer.

As for the QzROM product shipped after writing, “0016” (protect

enabled) or “FF16” (protect disabled) is written into the ROM code

protect address when Renesas Technology corp. performs writing.

The writing of “0016” or “FF16” can be selected as ROM option setup

(“MASK option” written in the mask file converter) when ordering.

<Notes>

(1) Because the contents of RAM are indefinite at reset, set

initial values before using.

(2) Do not access to the reserved area.

(3) Random data is written into the Renesas shipment test area

and the reserved ROM area. Do not rewrite the data in these

areas. Data of these area may be changed without notice.

Accordingly, do not include these areas into programs such

as checksum of all ROM areas.

(4) The QzROM values in function set ROM data 0 to 2 set the

operating modes of the various peripheral functions after an

MCU reset is released. Do not fail to set the value for the

selected function. Bits designated with a fixed value of 1 or

0 must be set to the designated value.

• Function set ROM Area

[Renesas shipment test area]

Figure 8 shows the Assignment of Function set ROM area.

The random data are set to the Renesas shipment test areas

(addresses FFD416 to address FFD716).

Do not rewrite the data of these areas.

When the checksum is included in the user program, avoid

assigning it to these areas.

[Function set ROM data] FSROM0, FSROM1, FSROM2

Function set ROM data 0 to 2 (addresses FFD816 to FFDA16) are

used to set modes of peripheral functions.

By setting values to these areas, the operation mode of each

peripheral function are set after releasing reset.

Refer to the descriptions of peripheral functions for the details of

operation of peripheral functions.

• Clock generating circuit (page 46)

• Watchdog timer (page 42)

• Low voltage detection circuit (page 44)

Rev.2.01 Oct 15, 2007 Page 11 of 81

REJ03B0210-0201

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