Rainbow Electronics AT91CAP9S250A - Manual (Page 740)

740
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
40.3 I/O Lines Description
Each channel outputs one waveform on one external I/O line.
40.4 Product Dependencies
40.4.1 I/O Lines
The pins used for interfacing the PWM may be multiplexed with PIO lines. The programmer
must first program the PIO controller to assign the desired PWM pins to their peripheral func-
tion. If I/O lines of the PWM are not used by the application, they can be used for other
purposes by the PIO controller.
All of the PWM outputs may or may not be enabled. If an application requires only four chan-
nels, then only four PIO lines will be assigned to PWM outputs.
40.4.2 Power Management
The PWM is not continuously clocked. The programmer must first enable the PWM clock in
the Power Management Controller (PMC) before using the PWM. However, if the application
does not require PWM operations, the PWM clock can be stopped when not needed and be
restarted later. In this case, the PWM will resume its operations where it left off.
Configuring the PWM does not require the PWM clock to be enabled.
40.4.3 Interrupt Sources
The PWM interrupt line is connected on one of the internal sources of the Advanced Interrupt
Controller. Using the PWM interrupt requires the AIC to be programmed first. Note that it is not
recommended to use the PWM interrupt line in edge sensitive mode.
40.5 Functional Description
The PWM macrocell is primarily composed of a clock generator module and 4 channels.
– Clocked by the system clock, MCK, the clock generator module provides 13
clocks.
– Each channel can independently choose one of the clock generator outputs.
– Each channel generates an output waveform with attributes that can be defined
independently for each channel through the user interface registers.
Table 40-1. I/O Line Description
Name Description Type
PWMx PWM Waveform Output for channel x Output