Thanks very much for the info. There seem to be a lot of RS-232 to TTL level converters around so this might not be such a big issue.
I have the sabertooth on a separate power switch. So I assume that after I boot the beagleboard, switching on the power to the sabertooth will keep them separate. On Friday, 3 January 2014 10:07:01 UTC-10, Nizamov Shawkat wrote: > > Hi, > > Unfortunately BB-xm does not carry TTL signals so you will need some level > converting interface. Guess that it is the same with BB. > > You might want to use the serial port - then you need RS-232 to TTL level > converter and you have to make sure that during initial bootup your > peripheral stays disconnected. > Or you might want to use some GPIO - they are 1.8v (2.8v for BB?). You > might setup pins in such way that you route some other serial port to GPIO. > In any case you will need a simple single transistor level converter. > > I have to do a similar thing in the future and I am going the analog way- > there is a plenty of I2C controllable DAC's (dual/quad channels) which you > will only need to connect to power supply, to I2C bus and driver board - no > other components are need. So in hardware it is almost as well simple, but > in programming it is going to be much much easier. > > Hope it helps, > Shavkat > > On Friday, January 3, 2014 5:16:19 AM UTC+1, Simon Engler wrote: >> >> Hello, >> >> I am trying to connect my beagleboard up to a sabertooth 2x10 >> >> http://www.dimensionengineering.com/products/sabertooth2x10 >> >> It is best for me to communicate through simplified serial if possible. >> Description below. >> >> Could someone point me in the right direction? >> >> Thanks. >> >> >> "Simplified serial uses TTL level single-byte serial commands to set the >> motor speed and >> direction. This makes it easy to interface to microcontrollers and PCs, >> without having to >> implement a packet-based communications protocol. Simplified serial is a >> one-direction only >> interface. The transmit line from the host is connected to S1. The host’s >> receive line is not >> connected to the Sabertooth. Because of this, multiple drivers can be >> connected to the same serial >> transmitter. If using a true RS-232 device like a PC’s serial port, it is >> necessary to use a level >> converter to shift the –10V to 10V rs-232 levels to the 0v-5v TTL levels >> the Sabertooth is >> expecting. This is usually done with a Max232 type chip. If using a TTL >> serial device like a >> microcontroller, the TX line of the microcontroller may be connected >> directly to S1. >> >> Because Sabertooth controls two motors with one 8 byte character, when >> operating in Simplified >> Serial mode, each motor has 7 bits of resolution. Sending a character >> between 1 and 127 will >> control motor 1. 1 is full reverse, 64 is stop and 127 is full forward. >> Sending a character between >> 128 and 255 will control motor 2. 128 is full reverse, 192 is stop and >> 255 is full forward. >> Character 0 (hex 0x00) is a special case. Sending this character will >> shut down both motors." >> >> >> >> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
