P87CL881H View Datasheet(PDF) - Philips Electronics
Part Name
Description
Manufacturer
P87CL881H
Philips Electronics
P87CL881H Datasheet PDF : 32 Pages
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Philips Semiconductors
Low-voltage microcontroller with 63-kbyte
OTP program memory and 2-kbyte RAM
Product specification
P87CL881H
6.3.1 AUX-RAM PAGE REGISTER (XRAMP)
The AUX-RAM Page Register is used to select one of the seven 256 bytes pages of the internal 1792-byte AUX-RAM
for MOVX-accesses via R0 or R1. Its reset value is ‘XXXX X000’ (AUX-RAM page 0).
Table 5 AUX-RAM Page Register (SFR address FAH)
7
6
5
4
−
−
−
−
3
2
1
0
−
XRAMP2 XRAMP1 XRAMP0
Table 6 Description of XRAMP bits
BIT
7 to 3
2
1
0
SYMBOL
−
XRAMP2
XRAMP1
XRAMP0
FUNCTION
reserved, undefined during read, a write operation must write logic 0 to these locations
AUX-RAM page select bit 2
AUX-RAM page select bit 1
AUX-RAM page select bit 0
Table 7 Memory locations for all possible MOVX accesses
ARD(1) XRAMP2 XRAMP1 XRAMP0
ACCESS
INSTRUCTION TYPE
0
0
0
0 AUX-RAM page 0 (address 0 to 255)
MOVX @ Ri, A and
0
0
0
1
AUX-RAM page 1 (address 256 to 511) MOVX @ A, Ri
0
0
1
0 AUX-RAM page 2 (address 512 to 767)
0
0
1
1 AUX-RAM page 3 (address 768 to 1023)
0
1
0
0 AUX-RAM page 4 (address 1024 to 1279)
0
1
0
1 AUX-RAM page 5 (address 1280 to 1535)
0
1
1
0 AUX-RAM page 6 (address 1536 to 1791)
0
1
1
1 no valid memory access
1
X
X
X external RAM locations 0 to 255
0
X
X
X AUX-RAM locations 0 to 1791 external MOVX @ DPTR, A and
RAM locations 1792 to 65535
MOVX A, DPTR
1
X
X
X external RAM locations 0 to 65535
Note
1. ARD (AUX-RAM Disable) corresponds to bit 6 in the Special Function Register PCON (address 87H).
1999 Apr 16
14
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