Table 3.1 on page 7 states that there are 12 PWM pins for the 1280, however the Port discriptions show that there are 15 PWM pins,
Port B = 4
Port E = 3
Port G = 1
Port H = 4
Port L = 3
Total = 15
Further more, a Schematic on SparkFun shows 5 pwm pins on Port E or a total of 17.
The Arduino Web site states that there are 14 pwm pins.
I know there are multiple uses for most of the pins, but Either I missed it in the documentation, or it just isn’t that apparent to a noob.
So which is correct? (or am I looking at an outdated spec sheet?)
THis is strange indeed…
Arduino homepage says 14pwm
So I do not know where those 3 extra come from at sparkfun
Mabie it’s software limitations, the timer used to do somthing else.
just my 2cents
The actual Arduino MEGA board shows PWMs 0 to 13, but pin 0 and 1 are also marked TX and RX and included as part of the communication.
According to the table 13-14 in the Data sheets, this is incorrect. It may be that that TX0/RX0 could be used as a PWM, but it is most likely used as the main TX/RX for communication, thus leaving us with 12 PWM as stated in the data sheet.
So that just leaves us with the one extra pwm to figure out.
After laying out the ATMEGA1280 in Eagle, I come up with 14 pwm pins as stated on the arduino page, but 2 more than what the data sheet states - and this is without useing the TXD0/RXD0 as shown on the Arduino MEGA board.
I got the answer on another forum,
There are only 12 16bit PWM channels and 3 8bit pwm channels. The table doesn’t show this.
1, 23, 18, and 26 is shared with OC0A and OC1C so it can be either 8 or 16 bit, which is where the 15 or 16 PWM pins come in. There are 16 pwm pins, but there are only 15 physical pins, 26 being shred gives you either 4, 8bit or 12 16 bit pins. But I’m not sure if both types can be used at the same time.