CP2400 SILABS [Silicon Laboratories], CP2400 Datasheet - Page 72

• Manufacturer Part Number: CP2400
• Description: 128/64 SEGMENT LCD DRIVER
• Manufacturer: SILABS [Silicon Laboratories]

CP2400/1/2/3
SFR Definition 11.1. RTCKEY: SmaRTClock Lock and Key
Address = 0x0A
72
Name
Reset
Type
Bit
7:0
Bit
RTC0ST
Name
7
0
SmaRTClock Interface Lock/Key and Status.
Locks/unlocks the SmaRTClock interface when written. Provides lock status when read.
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 RTC0ST = 0x00 (locked), writing 0xA5 followed by 0xF1 unlocks the SmaRT-
Clock Interface.
When RTC0ST = 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 RTC0ST = 0x02 (unlocked), any write to RTCKEY will lock the SmaRTClock
Interface.
When RTC0ST = 0x03 (disabled), writes to RTCKEY have no effect.
6
0
5
0
Rev. 1.0
4
0
RTC0ST[7:0]
R/W
Function
3
0
2
0
1
0
0
0