Datasheet

911
SAM4S [DATASHEET]
11100E–ATARM–24-Jul-13
38.7.30 PWM Write Protect Control Register
Name: PWM_WPCR
Address: 0x400200E4
Access: Write-only
• WPCMD: Write Protect Command
This command is performed only if the WPKEY value is correct.
0 = Disable the Write Protect SW of the register groups of which the bit WPRGx is at 1.
1 = Enable the Write Protect SW of the register groups of which the bit WPRGx is at 1.
2 = Enable the Write Protect HW of the register groups of which the bit WPRGx is at 1.
Moreover, to meet security requirements, in this mode of operation, the PIO lines associated with PWM can not be con-
figured through the PIO interface, not even by the PIO controller.
3 = No effect.
Note: Only a hardware reset of the PWM controller can disable the Write Protect HW.
• WPRGx: Write Protect Register Group x
0 = The WPCMD command has no effect on the register group x.
1 = The WPCMD command is applied to the register group x.
• WPKEY: Write Protect Key
Should be written at value 0x50574D (“PWM” in ASCII). Writing any other value in this field aborts the write operation of the
WPCMD field. Always reads as 0.
List of register groups:
• Register group 0:
– “PWM Clock Register” on page 882
• Register group 1:
– “PWM Disable Register” on page 884
• Register group 2:
– “PWM Sync Channels Mode Register” on page 890
– “PWM Channel Mode Register” on page 918
– “PWM Stepper Motor Mode Register” on page 910
• Register group 3:
– “PWM Channel Period Register” on page 922
– “PWM Channel Period Update Register” on page 923
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
WPRG5 WPRG4 WPRG3 WPRG2 WPRG1 WPRG0 WPCMD