I am wanting to use the standard official ethernet shield with a Due. The shield appears to use pins 10-13 for its own purposes (part of the SPI link, I guess), which unfortunately means that it consumes 4 of the PWM outputs on the Due. Now, seeing as the shield was designed for the Uno, and on the Uno only two of pins 10-13 are PWM (10 and 11), clearly the SPI link does not require all four pins to be PWM enabled.
Ideally I'd like to use all 12 PWM outputs on the Due for my own purposes. Is there any way of avoiding using pins 10-13?
On the Ethernet Shield page
, it says:
Arduino communicates with both the W5100 and SD card using the SPI bus (through the ICSP header). This is on digital pins 11, 12, and 13 on the Duemilanove and pins 50, 51, and 52 on the Mega. On both boards, pin 10 is used to select the W5100 and pin 4 for the SD card. These pins cannot be used for general i/o.
This is curious because the ethernet shield already uses the SPI pins via the 6-way header on the bottom of the board. Does it also need to use the extra four pins on the digital I/O rail?
Basically, I'd like to know: is it possible to create an ethernet connection with the Due and still use
all 12 PWM outputs?
If there's a way I can use the two DACs for the ethernet shield instead of the PWM outputs, that would work too.
Thanks a lot!