MS51
Dec. 17, 2019
Page
105
of 316
Rev 1.01
M
S51
SE
RIES
TE
CHNICA
L REF
ERE
N
CE MA
NU
A
L
TA
– Timed Access
Regiser
Address
Reset Value
TA
C7H, all pages
0000_0000b
7
6
5
4
3
2
1
0
TA[7:0]
W
Bit
Name
Description
7:0
TA[7:0]
Timed access
The timed access register controls the access to protected SFRs. To access protected bits, user
should first write AAH to the TA and immediately followed by a write of 55H to TA. After these two
steps, a writing permission window is opened for 4 clock cycles during this period that user may
write to protected SFRs.