P87C660X2 PHILIPS [NXP Semiconductors], P87C660X2 Datasheet - Page 76

• Manufacturer Part Number: P87C660X2
• Description: 80C51 8-bit microcontroller family
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
2003 Oct 02
80C51 8-bit microcontroller family
RAM, low voltage (2.7 to 5.5 V), low power, high speed (30/33
MHz), two 400KB I
NOTE:
*User software should not write 1s to reserved bits. These bits may be used in future 8051 family products to invoke new features. In that case, the reset or inactive value
of the new bit will be 0, and its active value will be 1. The value read from a reserved bit is indeterminate.
AUXR
Symbol
AO
EXTRAM
FME
SRD
—
Address = 8EH
Not Bit Addressable
Bit:
Function
Disable/Enable ALE
AO
0
1
Internal/External RAM access using MOVX @Ri/@DPTR
EXTRAM
0
1
Fast Mode Enable, switches between the Standard and the Fast data-transfer mode for the SIO1 I
one-time set bit, cleared by chip-reset only)
FME
0
1
Slew-Rate control-circuit Disable, switches between the minimum and the maximum slew-rate of the SCL1 and SDA1 pins
of the SIO2 I
SRD
0
1
Not implemented, reserved for future use*.
100
2
C interfaces
—
7
Figure 49. Internal and External Data Memory Address Space with EXTRAM = 0
2
256 BYTES
C serial port.
ERAM
Operating Mode
ALE is emitted at a constant rate of
in 6-clock mode).
ALE is active only during off-chip memory access.
Operating Mode
Internal ERAM access using MOVX @Ri/@DPTR.
External data memory access.
Operating Mode
100 Kbit/s Standard mode selected.
400 kbit/s Fast mode selected.
Operating Mode
Minimum output slew-rate.
Maximum output slew-rate.
—
6
16 KB OTP/ROM, 512B
FF
80
00
SRD
5
Figure 48. AUXR: Auxiliary Register
INTERNAL RAM
INTERNAL RAM
128 BYTES
128 BYTES
LOWER
UPPER
—
4
76
1
FME
/
FF
6
80
00
3
the oscillator frequency (12-clock mode;
FUNCTION
REGISTER
SPECIAL
—
2
EXTRAM
1
3FFF
0000
AO
EXTERNAL
P8xC660X2/661X2
0
MEMORY
DATA
Reset Value = xx0x 0x00B
1
/
2
3
C serial port (a
f
OSC
SU01750
Product data
SU01749