ML51/ML54/ML56
Sep. 01, 2020
Page
92
of 719
Rev 2.00
ML
51
/ML
54
/ML
5
6 S
E
RI
E
S
TECHNI
CA
L
RE
F
E
R
E
NC
E
M
A
NU
A
L
ML51/M
L54
/M
L56
Series
Tec
hnical Reference
Manual
SFRS
– SFR Page Selection
Register
SFR Address
Reset Value
SFRS
91H, All pages
0000_0000b
7
6
5
4
3
2
1
0
-
-
-
-
-
-
SFRPAGE[1:0]
-
-
-
-
-
-
R/W
Bit
Name
Description
[1:0]
SFRPAGE[1:0]
SFR Page Select
00 = Instructions access SFR Page 0.
01 = Instructions access SFR Page 1.
10 = Instructions access SFR page 2.
11 = Instructions access SFR page 3.
Switch SFR page demo code:
MOV SFRS,#00H
;switch to SFR Page 0
MOV SFRS,#01H
;switch to SFR Page 1
MOV SFRS,#02H
;switch to SFR page 2
MOV SFRS,#03H
;switch to SFR page 3
Timed Access Protection (TA)
6.1.7.2
The ML51/ML54/ML56 Series has several features such as WDT and Brown-out detection that are
crucial to proper operation of the system. If leaving these Register Description unprotected, errant
code may write undetermined value into them and results in incorrect operation and loss of control. To
prevent this risk, the ML51/ML54/ML56 Series has a protection scheme, which limits the write access
to critical SFR. This protection scheme is implemented using a timed access (TA). The following
registers are related to the TA process.
