Pin Description (Continued)
XTAL1
Input to the inverting oscillator amplifier and input to the
internal clock operating circuit.
XTAL2
Output from the inverting oscillator amplifier.
Special Function Registers
A map of the on-chip memory area called the Special
Function Register (SFR) space is shown in Table 1.
Table 1. AT48801 SFR Map and Reset Values
Note that not all of the addresses are occupied, and unoc-
cupied addresses may not be implemented on the chip.
Read accesses to these addresses will in general return
random data, and write accesses will have an indetermi-
nate effect.
User software should not write 1s to these unlisted loca-
tions, since they may be used in future products to invoke
new features. In that case, the reset or inactive values of
the new bits will always be 0.
Timer 2 Registers Control and status bits are contained
in registers T2CON (shown in Table 2) and T2MOD
(shown in Table 4) for Timer 2. The register pair
(continued)
0F8H
0FFH
0F0H
B
00000000
0F7H
0E8H
0EFH
0E0H
ACC
00000000
0E7H
0D8H
0DFH
0D0H
0C8H
PSW
00000000
T2CON
00000000
T2MOD
XXXXXX00
RCAP2L
00000000
RCAP2H
00000000
TL2
00000000
TH2
00000000
0D7H
0CFH
0C0H
0C7H
0B8H
IP
XX000000
0B0H
P3
11111111
0A8H
IE
0X000000
0A0H
P2
11111111
98H
SCON
SBUF
00000000 XXXXXXXX
90H
P1
11111111
88H
TCON
00000000
TMOD
00000000
TL0
00000000
80H
P0
11111111
SP
00000111
DPL
00000000
TL1
00000000
DPH
00000000
TH0
00000000
TH1
00000000
0BFH
0B7H
0AFH
0A7H
9FH
97H
8FH
PCON
0XXX0000
87H
1-4
AT48801