MS51
Nov. 28, 2019
Page
224
of 491
Rev 1.00
MS51
32K
SE
RIES
TE
CHNICAL RE
F
EREN
CE MA
N
UAL
AUXR1
– Auxiliary Register 1
Register
SFR Address
Reset Value
AUXR1
A2H , Page 0
POR: 0000 0000b,
Software reset: 1U00 0000b,
nRESET pin: U100 0000b,
Others: UUU0 0000b
7
6
5
4
3
2
1
0
SWRF
RSTPINF
HardF
SLOW
GF2
UART0PX
0
DPS
R/W
R/W
R/W
R/W
R/W
R/W
R
R/W
Bit
Name
Description
7
SWRF
Software reset flag
When the MCU is reset via software reset, this bit will be set via hardware. It is recommended
that the flag be cleared via software.
The software demo code is listed below.
ANL
AUXR0,#01111111b
;software reset flag clear
CLR
EA
MOV
TA,#0Aah
MOV
TA,#55h
ORL
CHPCON,#10000000b
;software reset
Boot Select
6.2.4.7
RST pin reset
Brown-out reset
Software reset
Low voltage reset
Load
Reset and boot from LDROM
Reset and boot from APROM
CONFIG0.7
CHPCON.1
Watchdog timer reset
BS
CBS
BS = 0
BS = 1
Hard fault reset
Power-on reset
Figure 6.2-3 Boot Selecting Diagram
The MS51 provides user a flexible boot selection for variant application. The SFR bit BS in
CHPCON.1 determines MCU booting from APROM or LDROM after any source of reset. If reset
occurs and BS is 0, MCU will reboot from address 0000H of APROM. Else, the CPU will reboot from
address 0000H of LDROM. Note that BS is loaded from the inverted value of CBS bit in CONFIG0.7
after all resets except software reset.