SAM3X8E Atmel Corporation, SAM3X8E Datasheet - Page 1000

• Manufacturer Part Number: SAM3X8E
• Manufacturer: Atmel Corporation

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Method 2: Manual write of duty-cycle values and automatic trigger of the update
SAM3X/A
SAM3X/A
In this mode, the update of the period value, the duty-cycle values, the dead-time values and the
update period value must be done by writing in their respective update registers with the CPU
(respectively PWM_CPRDUPDx, PWM_CDTYUPDx, PWM_DTUPDx and PWM_SCUPUPD).
To trigger the update of the period value and the dead-time values, the user must use the bit
UPDULOCK of the
allows to update synchronously (at the same PWM period) the synchronous channels:
After writing the UPDULOCK bit to 1, it is held at this value until the update occurs, then it is
read 0.
The update of the duty-cycle values and the update period is triggered automatically after an
update period.
To configure the automatic update, the user must define a value for the Update Period by the
UPR field in the
troller waits UPR+1 period of synchronous channels before updating automatically the duty
values and the update period value.
The status of the duty-cycle value write is reported in the
(PWM_ISR2) by the following flags:
Depending on the interrupt mask in the PWM_IMR2 register, an interrupt can be generated by
these flags.
Sequence for Method 2:
• If the bit UPDULOCK is set to 1, the update is done at the next PWM period of the
• If the UPDULOCK bit is not set to 1, the update is locked and cannot be performed.
• WRDY: this flag is set to 1 when the PWM Controller is ready to receive new duty-cycle
1. Select the manual write of duty-cycle values and the automatic update by setting the
2. Define the synchronous channels by the bits SYNCx in the PWM_SCM register.
3. Define the update period by the field UPR in the PWM_SCUP register.
4. Enable the synchronous channels by writing CHID0 in the PWM_ENA register.
5. If an update of the period value and/or of the dead-time values is required, write regis-
6. Set UPDULOCK to 1 in PWM_SCUC.
7. The update of these registers will occur at the beginning of the next PWM period. At
8. If an update of the duty-cycle values and/or the update period is required, check first
9. Write registers that need to be updated (PWM_CDTYUPDx, PWM_SCUPUPD).
10. The update of these registers will occur at the next PWM period of the synchronous
synchronous channels.
values and a new update period value. It is reset to 0 when the PWM_ISR2 register is read.
field UPDM to 1 in the PWM_SCM register
ters that need to be updated (PWM_CPRDUPDx, PWM_DTUPDx), else go to
this moment the bit UPDULOCK is reset, go to
that write of new update values is possible by polling the flag WRDY (or by waiting for
the corresponding interrupt) in the PWM_ISR2 register.
channels when the Update Period is elapsed. Go to
“PWM Sync Channels Update Period Register”
“PWM Sync Channels Update Control Register”
Step 5.
Step 8.
“PWM Interrupt Status Register 2”
for new values.
(PWM_SCUP). The PWM con-
for new values.
(PWM_SCUC) which
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
Step 8.