Post by thread:[SX] SX Sim truncating

In SX Microcontrollers, SX/B Compiler and SX-Key Tool, ShadowsSoldier wrote:I want to run my SX28 with a 5.120 MHz crystal oscillator. The SX Sim truncates it to 5MHz. As a result, my timing is off. Is there anything I can do to get the SX Sim not to do that?

Thanks, BBAL ---------- End of Message ---------- You can view the post on-line at: http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=107557 Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:I imagine that you can ask Guenther to add code for such. {I think it is in VisualBasic.} Alternatively, you could try runing it 10 times faster and adjust your read outs by dividing by ten. That would only give a ballpark figure as you would still be short by 0.200. Maybe, and just maybe you can get it to operate at 512Mhz and divide by 100. I am assuming that it won't accpet plain old Hz as a number, only Mhz.

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In SX Microcontrollers, SX/B Compiler and SX-Key Tool, g_daubach wrote:BBAL, until now, SXSim used a long variable to hold the specified clock frequency - this is why it truncated all "odd" values - shame on me! This is fixed in the meantime, and will come with the next release soon. Thanks for pointing out this bug!

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In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:How is that for response. Thanks Guenther. Since I also now know it will become available I can think of ways to use it too. Please be sure to document the convience.

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In SX Microcontrollers, SX/B Compiler and SX-Key Tool, ShadowsSoldier wrote:Thanks for that reply - I can estimate it like Kramer said. I just wanted to make sure I wasn't doing something like picking a "wrong MHz" crystal or something crazy like that. Thanks both to Geunther and Kramer.

-BBAL ---------- End of Message ---------- You can view the post on-line at: http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=107557#m107732 Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:I just talk, G�nther deserves the thanks. I must say that I have confidence in Parallax's desire toward excellence. I tried the 51Mhz and it worked fine, 512Mhz went nowhere. There are specific applications that may use an odd ball crystal to achieve a best fit [mostly things like MIDI's special Baud rate and using multiple ISRs for combined SPIs, RS232, and servos. These certainly will benefit from such.

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In SX Microcontrollers, SX/B Compiler and SX-Key Tool, g_daubach wrote:As a matter of fact, the MIDI baud rate of 32,000 baud can easily derived from even clock frequencies (much easier than "standard" rates like 38,400). I think this is why the guys who defined the MIDI standard have choosen this baud rate.

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In SX Microcontrollers, SX/B Compiler and SX-Key Tool, PJMonty wrote:G�nther, You are quite correct. Actually the MIDI baud rate is 31250, which sounds like a really "weird" baud rate becuase we're conditioned to 9600, 19200, 38400, etc. The fact is that back in the 80's when MIDI was created, microprocessors ran on rather slow clocks and the MIDI folk wanted an easy way to derive the baud from the same clock that drove the CPU. They were concerned about adding extra parts/cost to products. So, take a 1 MHz clock, divide it by 32 and what do you get? 31250, that's what. It meant that you could toss some flip-flips (remember those?) or other such soultions at the problem and get the clock to drive your UART.

[list]Thanks, PeterM[/list] ---------- End of Message ---------- You can view the post on-line at: http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=107557#m107794 Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:Ironicially, I always thought the opposite [That MIDI chose a special figure to make it hard for engineers to make a generic device]. Obviously, I hadn't done the math.

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In SX Microcontrollers, SX/B Compiler and SX-Key Tool, g_daubach wrote:Peter, yes, you are right - the MIDI baud rate is 31250, and not 32000 as I had stated before. Well, now that we have an SX device that can be clocked at 50 MHz, instead of just 1 MHz, here are the typical constants for the "standard" SX UART VP @ 50 MHz to handle the 31250 MIDI baud rate:

baud_bit = 3 start_delay = 13 int_period = 200 ---------- End of Message ---------- You can view the post on-line at: http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=107557#m107964 Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)