MS51
Dec. 17, 2019
Page
70
of 316
Rev 1.01
M
S51
SE
RIES
TE
CHNICA
L REF
ERE
N
CE MA
NU
A
L
AUXR1
– Auxiliary Register 1
Regiser
Address
Reset Value
AUXR1
A2H, all pages
POR 0000_0000b,
Software 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.
6
RSTPINF
External reset flag
When the MCU is reset by the external reset pin, this bit will be set via hardware. It is
recommended that the flag be cleared via software.
5
HardF
Hard Fault reset flag
Once Program Counter (PC) is over flash size, MCU will be reset and this bit will be set via
hardware. It is recommended that the flag be cleared via software.
Note:
If MCU run in OCD debug mode and OCDEN = 0, hard fault reset will be disabled and
only HardF flag be asserted.
4
SLOW
ADC Slow Speed Selection
This bit is used to select ADC low speed.
0 = high speed 500 ksps
1 = low speed 200 ksps
3
GF2
General purpose flag 2
The general purpose flag that can be set or cleared by the user via software.
2
UART0PX
Serial port 0 pin exchange
0 = Assign RXD to P0.7 and TXD to P0.6 by default.
1 = Exchange RXD to P0.6 and TXD to P0.7.
Note that TXD and RXD will exchange immediately once setting or clearing this bit. User should
take care of not exchanging pins during transmission or receiving. Or it may cause unpredictable
situation and no warning alarms.
1
0
Reserved
This bit is always read as 0.
0
DPS
Data pointer select
0 = Data pointer 0 (DPTR) is active by default.
1 = Data pointer 1 (DPTR1) is active.
After DPS switches the activated data pointer, the previous inactivated data pointer remains its
original value unchanged.