Rainbow-electronics AT89C5122 Manual de usuario descargar pdf (Pagina 24)

AT8xC5122/23

4202E–SCR–06/06

Registers

Reset Value = 0XXX X000b

Table 5. Auxiliary Register - AUXR (8Eh)

76543210

DPU - - - XRS0 EXTRAM AO

Bit

Number

Bit

Mnemonic Description

7DPU

Disable weak Pull-up

0 weak pull-up is enabled

1 weak pull-up is disabled

6-3 -

Reserved

The value read from this bit is indeterminate. Do not change these bits.

2XRS0

XRAM Size

0 256 bytes (default)

1 512 bytes

1 EXTRAM

EXTRAM bit

Cleared to access internal XRAM using MOVX @ Ri/ @ DPTR.

Set to access external memory.

Programmed by hardware after Power-up regarding Hardware Security Byte

(HSB), default setting , XRAM selected.

0AO

ALE Output bit

Cleared , ALE is emitted at a constant rate of 1/6 the oscillator frequency (or 1/3 if

X2 mode is used)(default).

Set , ALE is active only when a MOVX or MOVC instruction is used.

1 2 ... 19 20 21 22 23 24 25 26 27 28 29 ... 212 213

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Rainbow-electronics AT89C5122 Manual de usuario Pagina 24