driver issues (4516 and 4028 based)

hi, guys. i started a desktop milling machine project some time ago. my first concern was the stepper driver. since i'm on a tight budget, i was looking and discovering my options in that area. i stumbled upon a simple and cheap design (tom mcwire) and decided to give it a go. being an electronic technician (high school), the task shouldn't have been too difficult, right? not quite. i had some problems, since i didn't work with circuits for a few years. anyways, issues were solved, and circuits were made.
now, i am thinking about the l297 driver. is it possible to use this driver with different BoBs? i purchased one from ebay, and i am looking at the pminmo schematic, but, idiot as i am, i see 4 input connectors, and my BoB only has 3 outputs , and a gnd conn. also, can someone post a simplified version of a pminmo schematic? there are some stuff on it that i simply don't quite get. any help would be much appreciated!:cheers:

p.s. i am sorry for the thread title, but i wanted to ask about a different problem i encountered, which i solved in the meantime. problem was the step skipping with the mcwire driver and the kcam. problem was solved by switching off some options in Kcam, and setting the application priority to high.
http://www.kellyware.com/kwforum/dis...tml?1300245522

Can you provide more info? Specifically, can you give a diagram showing the outputs of your breakout board and the inputs to the driver board that has you concerned?

From a quick look at the schematic that you provided, it looks like the circuit wants to see an enable input, a step/clock input, a direction input, and ground from the breakout board.

Doesn't your breakout board provide those outputs?

If you don't have an enable output from the BOB, you should be able to hard-wire an enable connection on the driver board (I didn't stare at it long enough to decide whether you would need to ground it or just leave it floating - it looks like there are pull-up resistors on the inputs, so that if they are left unconnected then they will have a logic "high" asserted on those pins).

doorknob has it right. But another option is to replace your current BOB with one that is specifically designed for PMinMO drivers. :cough: such as the 4Axis5: BOB/Pulse/Power(PC Board ONLY) from massmind

i clearly uploaded the wrong photo. i'll update the right one in this post. i found this driver on ebay, along with the simple schematics, and thought i might try and produce one myself, but on it's schematic, the inputs were not labeled. on the pminmo schematic, the labels are clearly visible, but the schematic itself is still a bit complicated for me to make as a pcb layout. that's why i am asking if anyone got any simplified schematics. nevertheless i will try to simplify the one i have, and i'll post updates here, so any input is more than welcome.
thanks, guys

I'm still somewhat confused by what you have posted.

The original schematic that you posted was for a circuit using an L297 chip. That chip will take step and direction signals from a BOB and output drive signals that can control a stepper motor. However the L297 does not incorporate the high-power components that are required to actually drive the stepper motors. Rather, some kind of external circuitry is required to interface the L297 to the motor windings.

The second schematic that you posted was for an L298 chip. The L298 contains the high-power components that are required to drive the windings of a stepper motor. It can be coupled with an L297 (which provides the drive logic and signal conditioning for the motor windings).

The L298 is not designed to directly accept the step and direction signals from a BOB.

i feel quite dumb at the moment. i used the datasheets, and the datasheet i've got contains data for 3 ICs, l298n, l298hn and l297. i managed to overlook the fact that the last IC is not l297 but l298p. darn. so, in order to use l297 i need to use transistors or some other kind of "interface" to run the motor. excellent. now i fell a bit less dumb. i'll start working on my schematic right now:)

one more thing. can the l297 outputs control mosfets? specifically irf530 or irf630