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Supply, reset and clock management
ST7LITEUS2, ST7LITEUS5
This 16-bit register is read/write by software but can be written only once between two reset
events. It is cleared by hardware after a reset; When both MUXCR0 and MUXCR1 registers
are at 00h, the multiplexed PA3/RESET pin will act as RESET. To configure this pin as
output (Port A3), write 55h to MUXCR0 and AAh to MUXCR1.
These registers are one-time writable only.
●
To configure PA3 as general purpose output:
After power-on / reset, the application program has to configure the I/O port by writing
to these registers as described above. Once the pin is configured as an I/O output, it
cannot be changed back to a reset pin by the application code.
●
To configure PA3 as RESET:
An internally generated reset (such as POR, LVD, WDG, illegal opcode) will clear the
two registers and the pin will act again as a reset function. Otherwise, a power-down is
required to put the pin back in reset configuration.
Table 8.
Multiplexed IO register map and reset values
Address
(Hex.)
Register
label
7
6
5
4
3
2
1
0
0047h
MUXCR0
reset
value
MIR7
0
MIR6
0
MIR5
0
MIR4
0
MIR3
0
MIR2
0
MIR1
0
MIR0
0
0048h
MUXCR1
reset
value
MIR15
0
MIR14
0
MIR13
0
MIR12
0
MIR11
0
MIR10
0
MIR9
0
MIR8
0
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