Hi all,
for a smal project i need to send pulses from an io port to another device they need to be timed in verry short slices like

1 x 370µsec high and 3 x 370µsex low ... and so on. is this possible?
I know the gpioctl command but thats not the right way i guess.

so is the a way to do it with carambola and if so How?


thanks Stefan

One tip - this is a task for the microcontroller that is connected to carambola using I2C, RS232 or SPI ports.

This job is "mission Impossible" from user space. If You'd like make hard work, take a look at the kernel space ../drivers/ramips_wdt.c and modify code. But I don't recomend you do that.

It would be useful to know more about your application -- how big are the datagrams, and what precision is required?

You shouldn't need something as big/expensive as an Arduino -- any AVR should be able to buffer enough bytes to compensate for the non-real-time nature of Linux. You could easily stick a socket for an DIP-8 AVR in the proto area on the development board.

Alternatively, why doesn't someone integrate RTAI (https://www.rtai.org/) with the Carambola WRT fork? This might be a good starting point: https://github.com/bifferos/openwrt

You may want to take a look at how lirc solves this; they do IR bitbanging over a variety of interfaces; iirc that has about the same timing requirements.