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Member Since: November 27, 2011

Country: United States

  • Was going to order >$80. But with no back-order I ordered $20. Maybe later… Maybe not.

  • The 486 as introduced could not be used on a 386 motherboard and was not pin compatible.

    Later Cyrix introduced some 486 clones with a 386 compatible pinout and I heard some rare vendors introduced socket adapters which allowed the use of a 486 in a 386 motherboard. None of that was available until years after the 486 was on the market.

    But definitely influence is often more powerful than control. Look what happened to the IBM PC business when they introduced the PS/2 and tried to control the market instead of influencing it. How often have you used Microchannel lately compared to PCI?

  • Save 4 I/O lines by using 4-bit mode. Takes two writes but unless you are setting up the bits by hand flipping switches, you won’t see any speed difference.

    Save 1 I/O line by hard-wiring R/W to W (low). That means you cannot read the busy bit so you have to insert worst-case delays. This you might see a slow-down but usually not, especially if done carefully.

    That reduces the 11 required down to 6 with no additional hardware. It isn’t too hard to wire up a shift register (e.g. 74hc595) to reduce it further, especially if you are already using SPI (or SPI-like) and can share clock and data-out.

  • not multiples of 63. always multiples of 64. arithmetic precedence: (multiples of page size) - 1


    page size = 64
    integer multiples of the page size = N * 64
    start page M = M*64
    start page M+1 = (M+1)*64
    end page M = (M+1)*64 - 1
  • You could earn points if you explained how you cut it to the proper amperage and fastened it so you didn’t burn the connections.

  • If the pads on the SD wear out, or if the circuit is too noisy/unreliable in operation, just solder a single row of pins directly to the SD. Problem solved.

    Oh, now you want to read it somewhere else without using the arduino? Fine, make a pin socket adapter…

  • Yup, makes sense to me.

    I knew I’d seen this problem before… the Max Power IR kit and new version of said kit. :)

    Isn’t grounded emitter and load on the collector the recommended form? http://www.rason.org/Projects/transwit/transwit.htm http://www.kpsec.freeuk.com/trancirc.htm and http://en.wikipedia.org/wiki/Transistor all seem to think so.

    So on this board, we’d need to swap CE legs of the transistors (maybe mount them on the back side of the board) and reverse the LEDs and reverse the usage of pins 4,5 of JP6 (vcc and ground). I guess you could build the entire board on the back side… The only issue for me would be remembering that Vcc and GND are reversed on JP6.

    Oh, might also need to tweak the LED resistor values… I wonder if some of Nate’s variance with calculated values is because of emitter loading? (the emitter being offset from ground by 2v-4v)

  • to monitor the 485 bus while transmitting (for collision detection), would it work to separate pin 2,3 on the sp3485 and then ground pin 2? That would still leave transmitter control on the RTS, but would it then receive while it was sending?

No public wish lists :(