bobc Wrote: ------------------------------------------------------- > I'm not sure what "linear upgrade path" means > here. There are some PIC32 in a 28 pin packagge, > they are 3.3V, and of course not register > compatible with AVR, so not exactly a seamless > transition. > > NXP have announced some Cortex M0 parts in a DIP > package, also SO and TSSOP. I don't see any 4by Annirak - Controllers
I recently found the L6470 motor drivers. These are highly integrated, highly configurable drivers with interesting features like internal position counters, acceleration profiles, and 1/128 microstepping. Since they can be daisy-chained and they work over SPI, they sound like an excellent fit for an RPi solution. I shall have to do some more research, but they might work well for a no-processby Annirak - Controllers
rebecca.palmer Wrote: ------------------------------------------------------- > > However, I would add the > > additional constraint that the RPi must be able > to > > program, from bare metal... > > every daughter card. > > As the RPi has GPIOs, that doesn't require a > bootloader, only that the native programming mode > uses only 3.3V signals, which is tby Annirak - Controllers
R2C2 has nearly all of what I want to see out of ARM electronics. In fact, it is what I want for plain reprap operation. What would I change? I'd like to see provision for MAX31855 thermocouple readers. I'd like provision for more stepper motor drivers, but that's because I want to do some work with multi-extruder systems.by Annirak - Next Wave Electronics Working Group
I have a lot of respect for the designers of all of the generations of the reprap electronics (to be clear, that includes Gen 7). I think that we just have two very different approaches. There are three metrics we can judge hobbyist electronics by: price, performance, ease of manufacture. You have chosen ease of manufacture and price as priorities over performance. I'm choosing performance anby Annirak - Next Wave Electronics Working Group
Traumflug Wrote: ------------------------------------------------------- > Are they? So far I'm not aware of a chip with > hardware divide in a PDIP or other through hole > package. The important question is not whether a package is through-hole, it's whether it's hand-solderable. PLCC packages are easily hand solderable or can be used with through-hole sockets. SOIC packages are easiby Annirak - Next Wave Electronics Working Group
bobc Wrote: ------------------------------------------------------- > Yes, but 128K RAM and an SD card, compared to 3GB > and a HD! > > I think you have skewed the pros and cons quite a > lot to favour your preferred solution, but your > hopes for the STM32F4 are overly ambitious. > > Realistically, ethernet interface would be a nice > addition, though not essential,by Annirak - Next Wave Electronics Working Group
Traumflug Wrote: ------------------------------------------------------- > I'd consider the RPi to be more a replacement of > the host than a replacement of the controller. Generally speaking, I'd agree. However, the possibility of using several inexpensive microcontrollers essentially as PID controllers with segment buffers, all driven by a RPi is interesting. It separates the tasks intby Annirak - Next Wave Electronics Working Group
3D2B Wrote: ------------------------------------------------------- > Thanks Annirak. > > I did a gogle search before posting and saw laptop > PSUs, but the Amps seemed low compared with the > 22A of my hacked ATX supply. > > Is there a minimum amp rating I should be looking > for ? > (Would like to be able to run heated bed as well > as the usual steppers & hby Annirak - Controllers
A laptop power supply is pretty much ideal for this, which is why it's spec'd that way.by Annirak - Controllers
Traumflug Wrote: ------------------------------------------------------- > The bottleneck of the ATmegas is acceleration > calculation. This requires a 32-bit integer > division, people talk about 800 clock cycles or > more for this single thing. No better algorithm in > sight, unfortunately. But there are better processors in sight. In fact, they have been available for over 10by Annirak - Next Wave Electronics Working Group
mlpappin Wrote: ------------------------------------------------------- > tl;dr Are you, or do you know someone who might > be, interested in (using/ building/ collaborating > on design of/ discussing) a modular GPIO expander? > What features do you think it (should/ should not) > include? Short answer is yes. However, I would add the additional constraint that the RPi must be abby Annirak - Controllers
One possibility for a RPi-based solution would be small modules connected together with RS485, all controlled by the RPi. I think I could fit two stepper drivers, a PWM output, a SPI header and a small microcontroller on a 5 x 5cm board. I know that older-gen reprap electronics used a token-ring network and that was dropped. I'm thinking of something a little closer to a star network with a RPby Annirak - Next Wave Electronics Working Group
The way I see it, there are four ways for the community electronics to go from where they are now. 1. Stick with existing DIP ATMega solution (Gen7). This has enough power to do the job, can accept SD cards via SPI. It's not fancy, it's not expensive, it gets the job done. (Perhaps Traumflug can elaborate on the minimum BOM cost of this solution) 2. Switch to Arduino Due when available. Itby Annirak - Next Wave Electronics Working Group
bobc Wrote: ------------------------------------------------------- > Yes, I have seen that . In my non legal opinion > that "license" is completely bogus and should be > ignored. If they sell dev boards for less than the > price of the chip that is their choice but they > can't invent new laws to cover themselves. > > However, companies with such stupid ideas should > peby Annirak - Controllers
There are a few tradeoffs to make in choosing how to approach the host CPU card: The best option I can see would be for someone enterprising to start selling a ARM MCU + FT2232 header board at some shockingly low cost. Since that's not an option yet, the solutions I've found are: Olimex header boards: LPC-H1343 (8.95 EUR, Cortex-M3 @ 72MHz, 42 IO ) ***Only has 32 kB Flash, 8kB RAM STM32-H152 (by Annirak - Next Wave Electronics Working Group
I've been considering this for a while, and it seems to me that an ARM CPU would provide some benefits on a reprap. The chief among these actually being the availability of well priced development tools--see LPCXpresso and STM Discovery--as well as the GNU toolchain, though that works with AVR's too. In addition, many newer ARM CPUs support USB OTG or USB Host mode which could allow plugging aby Annirak - Next Wave Electronics Working Group
Looking at the STM32F4Discovery, it seems like a reasonable solution, but I'm concerned by the license which comes with it:by Annirak - Controllers
I've been working on a stepper motor driver board. This is somewhat related to the Gen7T. I'm trying to fit the design into a 10cm by 10cm area so that it can be produced inexpensively by iteadstudio. My control board will be another 10cm x 10cm board. I'm designing the motor controller with 6 stepper drivers so that it will be useful for testing multi-extruder configurations. To keep the boby Annirak - Next Wave Electronics Working Group
I've noticed that none of these designs seems to be using fuses on the motor power. Is that an oversight (it's recommended in the datasheet) or is it considered unnecessary? Also, Clarky: your board doesn't obey the power supply sequencing for the motor drivers. There are several people over at CNCZone who have experienced random failures on power-on, which might be related to this.by Annirak - Next Wave Electronics Working Group
Well, the more I look at this, the more I think that the RPi is unecessary. I'm in the process of hacking together a 6-axis motor control board, based on the TB6560AHQ--why six? Because I want to experiment with multiple extruders. Rather than step, decay, and torque select jumpers, I've decided to use three MCP23S17 GPIO expanders, since they actually occupy less board area, and I'm trying toby Annirak - Controllers
VDX Wrote: ------------------------------------------------------- > ... I have three of this drivers: > > > The biggest problem with them is - where to find a > controller capable of 10MHz stepping frequency I'd suggest using a FPGA. Generating 10MHz is pretty easy for them, since sub 10ns parts are widely available and inexpensive.by Annirak - Controllers
Perhaps I'm going about this the wrong way. I think I'll do the design with a LPCXpresso and I might make it standalone later on.by Annirak - Controllers
@nophead: I guess I wasn't particularly clear. Take a look at . The RPi doesn't have a lot of I/O, but it does have a fast UART, SPI port, and I2C port. Some kind of I/O expander will be necessary. Whether that's done with discrete logic or with an FPGA, CPLD, or MCU is the question. Discrete logic will be no less expensive than a small MCU. The advantage of an MCU is that it could have aby Annirak - Controllers
I've recently received my Raspberry Pi and I've been thinking about how it could be used for controlling a RepRap. The SPI port on the RPi is very scalable (it can be clocked over 100MHz, though you'll never see that data rate due to signal degradation), but the interrupt latency in the linux kernel could be a problem. As a result, I think the best bet is to stick a peripheral onto the RPi, eitby Annirak - Controllers
Hi Graham, I described my goals for this project in my first post. Microstepping is one of them. High current drive is a second. Why is this important? Well, it will lead to more motor options, not less. The more options, the better. grael Wrote: ------------------------------------------------------- > Hi Brendon, > > My real estate designated for steppers comes to > about 4"xby Annirak - Controllers
Well, I have my all through-hole design about 80% laid out, and the size is a bit of an issue. My stepper driver, implemented in through-hole, takes about 2"x6". With this in mind, I'm considering a mostly SMD approach. The goal here would be to use all easily solderable devices, so I would ultimately try not to use devices with a pitch of 0.5mm or lower. 0.8 seems to be easily solderable, soby Annirak - Controllers
Hi Larry, Pointers are one reason that I believe that people should start with an understanding of assembly language. Graham, As Larry points out, pointers are frequently poorly explained. Here's my best shot at it. A computer program only ever stores a constant directly. That is, constants are frequently tacked on to the end of an instruction. Variables are not. A variable is stored at soby Annirak - Controllers
The H21LTB is the totem-pole output version of the H21LOB. Generally, the H21LTB will replace the H21LOB, but it will not work in a circuit where several H21LOBs are ganged together, as these use the Open Collector.by Annirak - Controllers
Grael, The best book to learn C from is, hands down, "The C Programming Language" by Brian Kernighan and Dennis Ritchie. Ritchie is the original author and implementer of C and is, therefore, the leading authority. This book is also known as "the white bible," which should give you some idea of how widely respected it is. "Because the book was co-authored by the original language designer, andby Annirak - Controllers