SAB80535 Ver la hoja de datos (PDF) - Siemens AG

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SAB80535

8 Bit Single-Chip Microcontroller

Siemens AG 

SAB 80515/80535

Program memory

The SAB 80515 has 8 Kbyte of on-chip ROM, while the SAB 80535 has no internal ROM. The

program memory can be externally expanded up to 64 Kbytes. If the EA pin is held high, the

SAB 80515 executes out of internal ROM unless the address exceeds 1FFFH. Locations 2000H

through 0FFFFH are then fetched from the external program memory. If the EA pin is held low,

the SAB 80515 fetches all instructions from the external program memory. Since the SAB

80535 has no internal ROM, pin EA must be tied low when using this component.

Data Memory

The data memory address space consists of an internal and an external memory space. The

internal data memory is divided into three physically separate and distinct blocks: the lower 128

bytes of RAM, the upper 128 bytes of RAM, and the 128-byte special function register (SFR)

area. While the upper 128 bytes of data memory and the SFR area share the same address

locations, they are accessed through different addressing modes. The lower 128 bytes of data

memory can be accessed through direct or register indirect addressing; the upper 128 bytes of

RAM can be accessed through register indirect addressing; the special function registers are

accessible through direct addressing.

Four 8-register banks, each bank consisting of eight 8-bit multi-purpose registers, occupy loca-

tions 0 through 1FH in the lower RAM area. The next 16 bytes, locations 20H through 2FH, con-

tain 128 directly addressable bit locations. The stack can be located anywhere in the internal

data memory address space, and the stack depth can be expanded up to 256 bytes.

The external data memory can be expanded up to 64 Kbytes and can be accessed by instruc-

tions that use a 16-bit or an 8-bit address.

Semiconductor Group

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