C8051F410/1/2/3
SFR Definition 20.1. RTC0KEY: smaRTClock Lock and Key
R/W
Bit7
R/W
Bit6
R/W
Bit5
R/W
Bit4
R/W
Bit3
R/W
Bit2
R/W
Bit1
R/W
Reset Value
00000000
Bit0
SFR Address:
0xAE
Bits 7–0: RTC0STATE. smaRTClock State Bits
Read:
0x00: smaRTClock Interface is locked.
0x01: smaRTClock Interface is locked. First key code (0xA5) has been written, waiting for
second key code.
0x02: smaRTClock Interface is unlocked. First and second key codes (0xA5, 0xF1) have
been written.
0x03: smaRTClock Interface is disabled until the next system reset.
Write:
When RTC0STATE = 0x00 (locked), writing 0xA5 followed by 0xF1 unlocks the smaRTClock
Interface.
When RTC0STATE = 0x01 (waiting for second key code), writing any value other than the
second key code (0xF1) will change RTC0STATE to 0x03 and disable the smaRTClock
Interface until the next system reset.
When RTC0STATE = 0x02 (unlocked), any write to RTC0KEY will lock the smaRTClock
Interface.
When RTC0STATE = 0x03 (disabled), writes to RTC0KEY have no effect.
180
Rev. 1.0
SILICON [ SILICON ]
