C8051F709-GQR Silicon Labs, C8051F709-GQR Datasheet - Page 156

• Manufacturer Part Number: C8051F709-GQR
• Description: 8-bit Microcontrollers - MCU 8kB 32B EEPROM Cap Sense
• Manufacturer: Silicon Labs

Specifications of C8051F709-GQR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

C8051F70x/71x
23.4. EEPROM Security
RAM can only be downloaded to EEPROM after firmware writes a sequence of two bytes to EEKEY. In
order to enable EEPROM writes:
1. Write the first EEPROM key code byte to EEKEY: 0x55
2. Write the second EEPROM key code byte to EEKEY: 0xAA
After a EEPROM writes have been enabled and a single write has executed, the control logic locks
EEPROM writes until the two-byte unlock sequence has been entered into EEKEY again.
The protection state of the EEPROM can be observed by reading EEPSTATE (EEKEY2:0). This state can
be read at any time without affecting the EEPROM’s protection state.
If the two-byte unlock sequence is entered incorrectly, or if a write is attempted without first entering the
two-byte sequence, EEPROM writes will be locked until the next power-on reset.
SFR Definition 23.1. EEADDR: EEPROM Byte Address
SFR Address = 0xB6; SFR Page = All Pages
156
Name
Reset
7:5
4:0
Bit
Type
Bit
EEADDR[4:0]
Unused
Name
R
7
0
Read = 000b; Write = Don’t Care
EEPROM Byte Address
Selects one of 32 EEPROM bytes to read/write.
R
6
0
R
5
0
Rev. 1.0
4
0
Description
3
0
EEADDR[4:0]
R/W
2
0
1
0
0
0