 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Microcontroller and PC projects : Introducing the Colour Maximite 2
  Page 17 of 25   |
|||||
| Author | Message | ||||
Sasquatch Senior Member  Joined: 08/05/2020 Location: United StatesPosts: 296 |
I think Peter probably meant 74HC595 ? There are lots of online tutorials on using this chip as a serial - parallel expander. Just do a search for "Arduino 74HC595" and you will find all kinds of information. -Carl |
||||
| Decoy Senior Member Joined: 02/08/2019 Location: DenmarkPosts: 109 |
I have both the 74HC595's and the MCP23017's lying around. Is the speed difference large, comparing the shift register with the port expander? Also, should special considerations be taken regarding the drain on the Maximite 2? Would it be able to drive 2-3 MCP23017's or 74HC595's? |
||||
| Sasquatch Senior Member Joined: 08/05/2020 Location: United StatesPosts: 296 |
Driving the '595 chips shouldn't be a problem. Depending on what you are driving with the '595 chips could use a lot of power (i.e. LEDs or Relays) Using the hardware SPI to drive the '585 chips should be really fast. The '585 chip will clock the data on the "leading" or rising edge of the clock so you will need to be sure that the SPI port is configured properly. You will also need an additional I/O to drive the latch on the '585 output. You could also bit-bash the data to the '585 on any 3 I/O lines but it would be much slower than SPI. Also, The '585 chips only work as outputs, you would need another solution to read or scan additional inputs. The MCP23017 is a more sophisticated device and will do input or output on one of the I2C ports. The MCP23S17 appears to be the same device with SPI interface. Edited 2020-05-27 07:10 by Sasquatch -Carl |
||||
CaptainBoing Guru  Joined: 07/09/2016 Location: United KingdomPosts: 1985 |
Remember; Shift registers will be output only, so the O but not the I of I/O. If you are good with that then 595s are dead easy to implement on a 8-10MHz SPI and super cheap (I just saw 20x for Ģ2.09 all in). |
||||
| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 3552 |
When using discrete logic, please evaluate your output level needs. The 74HC595 can be powered from 3.3V and will output 3.3V logic levels The 74HC595 can be powered from 5V and will output 5V logic levels but is NOT 3.3V logic compatible at the inputs. It may work in some cases, but no guarantee. The 74HCT595 must be powered from 5V and will output 5V levels. But the inputs are 3.3V logic compatible. I do not own a CMM2 yet, but have succesfully used both on CMM and on micromites. I also tested the PCF8574 (that chip is driven from I2C and can be both input and output in any combination of the 8 bits). The PCF8574 is powered from 5V, drives 5V levels, and the inputs (I2C) are 3.3V compliant. Despite the fact that I2C is 400kHz max on this chip, and SPI to the 595 can run at higher speeds, I have not found major differences in speed when driving the outputs. Speed test is done on a 40MHz micromite MX170, and the whole update of the 8 bits was always within 1 msec (far faster than the mechanical relays I was driving). I assume the basic code is the dominant factor for this timing, not the serial data transport. Volhout Edited 2020-05-27 16:56 by Volhout PicomiteVGA PETSCII ROBOTS |
||||
| Decoy Senior Member Joined: 02/08/2019 Location: DenmarkPosts: 109 |
Thanks guys, I love thorough explanations. I will be referencing your posts when I get the Maximite 2 assembled. I just ordered the PCBs and I am sourcing parts now. Thanks! |
||||
| zeitfest Guru Joined: 31/07/2019 Location: AustraliaPosts: 386 |
I am looking at platforms/boards and wonder what programming the STM32H743IIT6 in C is like ? Is the IDE OK for a play or is it a severe learning curve before results ? |
||||
| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8592 |
V5.05.02RC40 Fixes bug in ON ERROR command Fixes lack of response to Ctrl-C when using a USB keyboard and calling PIN functions which involve ADC conversion in a tight loop NB: full change log is in the readme.txt file http://geoffg.net/Downloads/Maximite/Colour_Maximite_2_MMBasic.zip Edited 2020-05-28 21:40 by matherp |
||||
| Decoy Senior Member Joined: 02/08/2019 Location: DenmarkPosts: 109 |
Regarding using the Maximite 2 for embedded applications: The manual states that the Maximite 2 can run without a VGA-monitor, but can it also run without keyboard (including the USB- Serial converter IC) and other stuff? For embedded use it would be nice to be able to create the program on a complete Maximite, but the run the program on a board where I can omit VGA-connector + resistors, power switch, USB (for keyboard), IC for USB to serial and so on. Thanks! |
||||
| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8592 |
The CMM2 will run without any peripherals connected. You can explicitly disable the USB keyboard with OPTION USBKEYBOARD DISABLE. This stops the code polling so may increase performance very very slightly. The CMM2 will even run without a SDcard on power up if you use OPTION AUTORUN ON and if the program doesn't use the SDcard. Of course this isn't its design intention and the ArmmiteH7 is just as fast and has more I/O and the Nucleo-H743ZI2 is cheaper than the Waveshare |
||||
| Decoy Senior Member Joined: 02/08/2019 Location: DenmarkPosts: 109 |
Thanks! Yes, I understand that it is not the intended design of the CMM2, but it is amazing that it can meet my secondary wishes :) |
||||
| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8592 |
V5.05.02RC41 Fixes a bug where Ctrl-K in the editor would jump to the start of file if directly preceded by the HOME key Introduces a minor limitation on selection of text in the editor such that you can't select backwards from the point at which you pressed F4. You can go forwards and then reduce the selection by going back but you can never go back past the point you started the selection. This will affect LEFT, HOME and UP commands while in selection mode. Key presses that attempt to select back beyond the start point will be ignored NB: full change log is in the readme.txt file http://geoffg.net/Downloads/Maximite/Colour_Maximite_2_MMBasic.zip |
||||
| flasherror Senior Member Joined: 07/01/2019 Location: United StatesPosts: 159 |
Not sure who to address this to, but a reminder that the wikipedia article on Maximite should be updated for CM2 https://en.wikipedia.org/wiki/Maximite Edited 2020-05-29 23:30 by flasherror |
||||
thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
Thanks Peter, seems to fix the reported issues. Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
||||
Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3165 |
Good point... when it is officially released in the Silicon Chip mag (in about 3 weeks). Geoff Geoff Graham - http://geoffg.net |
||||
| Decoy Senior Member Joined: 02/08/2019 Location: DenmarkPosts: 109 |
I wonder, is it possible to order exactly that issue of Silicon Chip? |
||||
| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3661 |
Ask a newsagent. (Here, they'll get almost anything with some notice, though never tried an Oz one.) John |
||||
Poppy Guru Joined: 25/07/2019 Location: GermanyPosts: 486 |
They run an ONLINE-SHOP Apparently you can get online access HERE or order a printed back issue HERE right now the June issue already seems to be available, so consequently the July issue should be out in a month as well. But I wonder if itīs worth it, actually I donīt think you will find more specific informations in it than right here around. But in case of just fan-stuff collecting ... go ahead!   Andre ... such a GURU? | ||||
| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3661 |
Good points! Also, any questions if someone has a kit of parts have a great chance of getting answers here... John |
||||
| GregZone Senior Member Joined: 22/05/2020 Location: New ZealandPosts: 114 |
I had wondered why CMM2 didn't have any mention yet on Geoff's own website. Just figured that the Silicon Chip publishing agreement must have included some sort of embargo on publishing information elsewhere? Do you know if it's a single July issue article, or if is going to be maybe a 2 - 3 issue more indepth project series? Just deciding if I should invest in one of their 6 month hard-copy subscriptions, so I have the relevant issue(s) ... for collectability. To join my large collection of EA / ETI / Byte etc. etc. LOL |
||||
| Page 17 of 25 |
|||||
 Print this page |
