I haven't read up on stepper motor control theory recently, but this is how I understand it ? Half step winding power up states: a+ b+ a- b- (repeat) Full step winding power up states: a+, b+ a-, b+ a-, b- a+, b- (repeat) The way I've done it before, and am doing at the moment, is interspersing them: a+ a+,b+ b+ a-,b+ a- a-, b- b- a+, b- (repeat) Looking at the direct drive states to the windby grael - Mechanics
I don't agree about collisions. UARTS have been implemented with framing error detection for over a decade, and on all the microcontrollers I've dealt with, over more time than that. If you want to bit bang, it's a different matter, but again, most micros come with UARTs these days, and the larger ones with more than one. Parity also comes as a standard option, and can be implemented when bitby grael - Controllers
Curiously, I tried again on the 32 bit 8-nibble look up table, and it works now All I can conclude, is that (I had a select case type statement,) and I may have previously unbalanced it with a delay external to the case selection body. It's running now anyway, and it's smoother, I can get about 25% more speed by interspersing single and dual coil drive.by grael - RepRap Host
Hi nophead, I'm using u32 values, where I'm assuming the u means unsigned. /*port, position in table, least sig bit of nibble to change.*/ /*invocation: SteppinOut(GPIO? ,tableindex 0 to 7, offset); */ void SteppinOut(GPIO_TypeDef* GPIOx, u8 pos, u8 LS { u32 temp; u32 temp2; temp = (0x15462A89 >> (pos * 4)) & 0x0000000F; temp2 = temp ^ 0xF; temp = temp << LSB;by grael - RepRap Host
I got a stepper motor going with my board last night ! Only problem, is I thought I would try to finesse the steps a little, and go from coil 1 to coil 1+2 to coil 2 to coil 2+1 to coil 1 etc. I assumed the complier could handle a right shifting a 32 bit value an arbitary number of bits, especially since the chip has a built in barrel shifter. However, it gets confused, even if I try only 4 stby grael - RepRap Host
jeffpark_ Wrote: > I was wondering what software/toolchain are you > using to write/compile/upload code to the ARM? > I've got a couple Cortex-M3s (just the > microcontroller/breakout boards) I've been > thinking of coding for, but just haven't had to > time to research them. Hi Jeff, I've been using the tool chain that came with the STM circle first version, by Raisonance.by grael - RepRap Host
As my first circuit board appears to have operational hardware, I am now shifting focus on the build process over to the software forum on a new thread in the software forum, where you will also find the full hardware specification: Graham Daniel.by grael - Controllers
Background: On the first day of this year (1/1/2009), I made a personal commitment to build myself a CNC machine. (Please bear with me now, there is some hardware discussion that ought to go here for the record, and as background for the software design phase.) There are many options for control of CNC additive , subtractive, or scanning control electronics, Zack's modular board designs ( ), aby grael - RepRap Host
Weekend almost gone, but I'm making progress. I got a working program to toggle the state of my status LEDs. I extended it to control the piezo. I extended it to control 3 of the 5 darlington transistors, but it wouldn't turn on the last two. After about 6 hours of research, I found a first, and then second configuration setting to turn the JTAG port off successfully, and thereby allow GPIOB pby grael - Controllers
Hi Brendon, To date, my embedded programming was 98% assembly, so I know pointers, table jumps etc. Generally, I coded them in manually. It's getting to grips with C syntax that I'm working on now, that, and figuring my way through Raisonance's include files. Things like tracking down why GPIOB definitions work in main.c, but GPIOA definitions don't. Getting to know the library functions and C asby grael - Controllers
The cement is wet and lowering conductivity ?by grael - Controllers
I found some on line C reference material by those authors, I'd actually browsed some of the history a few years beck, but it looks worth studying, thanks guys !by grael - Controllers
Nice work Brendan, I would be trying to layer my software internally on my integrated PCB too, the difference being, that a request can be passed through internal memory and interrupt polling, or even direct calling of appropriate routines. In theory, I could have a set of commands for different "hardware modules" and even use the MMU to read the alerts and write the actions, whether I strive foby grael - Controllers
Way back when I first started using PICs, I wrote my own programmers. they didn't have very many devices at first (16F84), and then they started expanding their offerings rapidly. At first, I did a program for each chip, and compiled it to an .EXE, but then I gave up, and bought a PICSTART+. Here's one of the old programs I used, as a guide for you. If you want, PM me, and I can send you some EXby grael - Controllers
Thanks Brendon, I've seen many references to that book over the years, but not the book itself yet ! I'm feeling a lot better about the whole development process now anyway, I have been going through the STM pheripherals, the remap process, the analogue to digital, the MMU, the interrupts, and it's all looking really good. Lots of features to make life easy and improve performance on this STMby grael - Controllers
Hi Larry, JBB. Thanks for the written support and tips ! Not sure if this will show as an in line image or not, but this is the assembled board, mounted via sticky standoffs on the side of my XP EEEBOX, on a PC PSU, on top of 13 more circuitboards. One blank PCB in the background. The USB is connected but dormant so far, the serial is connected to the EEEBOX via a USB to serial convertor (serialby grael - Controllers
It depends what your budget is. The recommended/official parts are all very modular, so a high cost is allocated to extra connectors and PCB space, holes to house them, and repitition of things like mounts, mounting holes etc. You could go down the road I am, and make a new motherboard with higher integration, that can certainly bring the costs down. There are a lot of decisions to be made downby grael - General
Hi Korndog, that link is a dud...by grael - RepRap Host
I have one of the circuit boards populated now, all but for a LCD and the contrast potentiometer. It took me a few goes to get the STM32 microcontroller working, in getting up to speed with KiCad, I had found out that KiCad copper fills are much easier to remove, than they are in the version of Protel I used to use. So, I had placed a small 3.3 volt fill on the top side, and then, thinking the Kby grael - Controllers
davidgoodenough Wrote: > In my book the only way to design a good system is > to know what problem you are trying to solve. > Otherwise you can never know if you have solved > it. To be fair, Annirak has been involved in some discussion of that sort on other threads, but you do make a good point. I think, a very quick summary, (and I might easily miss some important possibilitiby grael - Controllers
What crystals are being used in the RRRF motherboards ? I'm still considering a crystal for my machine, from memory, I used to use 3.6864 MHz, or 7.3728 MHz quite a lot, because I could do perfect real time clock divisions, also I could get some useful baud rates with them. I need to check if these, or a multiple of them will get my factory boot loader running on the STM32F103VBT6 chips I'm usinby grael - Controllers
Annirak Wrote: ------------------------------------------------------- > -Addresses > First we must decide if device addresses should be > assigned by the bus controller or preprogrammed by > the developer. I think the best option is > probably to take a third approach, which is > similar to I2C. Different classes of device > should have different base addresses which haveby grael - Controllers
Finally, I have something I can hold in my hands. It's about 4/5 the height and width of a sheet of A4. Excellent quality reproduction, and the via holes all look very well aligned. I'll place an order tomorrow for the components I don't have, Hopefully I'll have enough parts by the weekend to start some programmingby grael - Controllers
Viktor, I have done some lost wax casting successfully with a mixture of portland cement, silica sand and chopped glass fibres. It was nasty to get off the finished article though ! I think less glass fibres might have helped... I put them in to keep the structure intact if there was any cracking, but with preheat, I has no problems with cracking whatsoever. Graham.by grael - Plastic Extruder Working Group
I forgot to mark this thread. Annirak wrote: " An N-bit CRC offers * 100% detection of single-bit errors; * 100% detection of all adjacent double-bit errors; * 100% detection of any errors spanning up to N-bits; * 100% detection of all two-bit errors not separated by exactly 2^N-1 bits * For arbitrary multiple errors spanning more than N bits, at worst 1 in 2^N failures On that basis, we only nby grael - Controllers
Hi Annirak, JBB. Definitely worth some consideration. I saw Zach put a couple of RJ45 on his latest motherboard. I considered it, as I had still to finalize my PCB order from Hong Kong, but decided against it, as I know, from the service angle, how frustrating it can be to have connections requiring specialist tools, and not to have that tool. You can get RJ45 crimpers at a reasonable price, buby grael - Controllers
I think there's already some discussion somewhere on the web about this, of course engineering grade wax has been around, and available for CNC work for some time already. Deposition CNC doesn't have as many advantages for wax though, as waste wax is very easily recycled anyway. The toolpaths are very different though...by grael - General
I think Zach's leaving the store and setting up his own one is good. When you are in business for yourself, decisions don't have to be run past such a large committee, and so you can streamline things that would otherwise be diabolically segmented, conditional, articulated etc. Not only that, but I've been designing my own version of a CNC/extruder motherboard, and having Zach as a proper opposiby grael - General
I think the Sanguino might be a bit big for that ? What's sort of device is outputting/inputing those voltage levels ? If you are inputting to tha sanguino, you could put three diodes in series, pointing towards the signal source, in series with a 10 k resistor to 5 volts on your sanguino. Tie the negatives together of the sanguino and your signal ground, and the signal input will be offset byby grael - Controllers
I'm expecting to order 15 sample PCBs shortly, on a two week processing cycle. I've added substantial ground planes, 12 volt plane, 5 volt plane and 3.3 volt plane areas. I decided to fit an SMD SD-card connector to the PCB (sourced from Jaycar), and to leave my 10 pin header for custom expansion. I have some local friends who are interested, and I'm thinking that I could use more than one herby grael - Controllers