Datasheet

209
SAM9X25 [DATASHEET]
11054E–ATARM–10-Mar-2014
22.13.20PMC Write Protect Mode Register
Name: PMC_WPMR
Address: 0xFFFFFCE4
Access: Read-write
Reset: See Table 22-3
• WPEN: Write Protect Enable
0 = Disables the Write Protect if WPKEY corresponds to 0x504D43 (“PMC” in ASCII).
1 = Enables the Write Protect if WPKEY corresponds to 0x504D43 (“PMC” in ASCII).
Protects the registers:
• “PMC System Clock Enable Register” on page 188
• “PMC System Clock Disable Register” on page 189
• “PMC Clock Generator Main Clock Frequency Register” on page 196
• “PMC Clock Generator PLLA Register” on page 197
• “PMC Master Clock Register” on page 198
• “PMC USB Clock Register” on page 200
• “PMC Programmable Clock Register” on page 202
• “PLL Charge Pump Current Register” on page 208
• WPKEY: Write Protect KEY
Should be written at value 0x504D43 (“PMC” in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
31 30 29 28 27 26 25 24
WPKEY
23 22 21 20 19 18 17 16
WPKEY
15 14 13 12 11 10 9 8
WPKEY
76543210
———————WPEN