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Post AvUvk7jpNfGvxADI2a by [email protected] |
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More posts by [email protected] |
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Post #AvUvk6o2qV3F3xB8yW by [email protected] |
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With 286 and 386 stalled for the moment, I'm thinking back to the 8087 situ… |
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Post #AvUvk6uQSm9hNkAEvA by [email protected] |
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Plus there's no guarantee that the 8087 tolerates 3V. It's a toasty chi… |
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Post #AvUvk70o53G9hX9Kro by [email protected] |
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The Arduino Giga has a STM32H747 for its main CPU, which is a dual core design … |
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Post #AvUvk77tegvm3WSzuy by [email protected] |
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It's possible on an Arduino to make a basic clock by setting a GPIO pin int… |
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Post #AvUvk7DvIHkeMDHoJM by [email protected] |
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The STM32H747 however has a whole crap ton of internal timing facilities. Chec… |
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Post #AvUvk7JaxCHwdnwL9U by [email protected] |
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What we're interested is over on the Advanced Peripheral Bus 1, where we fi… |
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Post #AvUvk7Pcan6owUl9Xs by [email protected] |
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You know what else was a 16-bit, auto-reloading counter? The Intel 8253 in the … |
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Post #AvUvk7WMBkUrHNuX2m by [email protected] |
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We can drive the timer counter clock from different sources, but the internal i… |
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Post #AvUvk7dRlOATdNEC5w by [email protected] |
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The GPIO registers have a rather confusing matrix of Alternate Functions. Up t… |
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Post #AvUvk7jpNfGvxADI2a by [email protected] |
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Bit 7 of GPIO register Port A can be mapped to timer channel 14's output, i… |
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Post #AvUvk7quxIwYJ9Wx5k by [email protected] |
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But we want a square wave. Luckily, there's a feature for that using the ti… |
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Post #AvUvk7xIZa30cwW32O by [email protected] |
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A divisor of 12 (10Mhz) and a period of 2 (for two clock edges) gives us pretty… |
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Post #AvUvk83KDArsvdKrQm by [email protected] |
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@gloriouscow how do you probe it? Are you sure it isn't the ground wire of … |
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Post #AvUvk88zs5PBDDzOGu by [email protected] |
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@hennichodernich That's just it, I'm not sure of anything. what makes a… |
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Post #AvUvk8EJYJetTiTdYm by [email protected] |
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@gloriouscow well, a steep slope...You need to use the ground spring instead of… |
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Post #AvUvk8KLBuTlmPIRxA by [email protected] |
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There's just one little problem. The 8086 and 8087 specify a 33% duty cycle… |
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Post #AvUvk8L39H2vobd13g by [email protected] |
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@hennichodernich Neat, thanks. I wonder if I can find that thing. :D |
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Post #AvUvk8VKX3GmKURE5A by [email protected] |
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@hennichodernich Thanks that did reduce the ringing a lot. I was wondering wha… |
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Post #AvUvk8iRkHlGzAZhWi by [email protected] |
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But look at the other modes available in the datasheet - PWM mode 1 looks inter… |
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Post #AvUvk97yDOB6GKW5JI by [email protected] |
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Now we have our square wave with the appropriate 33% duty cycle. Messing aroun… |
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Post #AvUvk9X8hoJLWOIBXc by [email protected] |
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Maybe... a capacitor might help? Capacitors are magic right? |
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Post #AvUvk9wfAujAnYEZKC by [email protected] |
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Anyway, if the 8086 & 8087 are running at full speed what's the plan fo… |
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Post #AvUvkALpfKrQ3c0fYW by [email protected] |
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The READY line prevents the 8086 and 8087 from completing bus transfers. If RE… |
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Post #AvUvkAjaF1rLFH7dZo by [email protected] |
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Then in our main program loop, we can read the bus signals from the 8288. If th… |
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Post #AvUvkBAWcrPUapj9ZQ by [email protected] |
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The only trick is that we have to very quickly reset READY low again or we may … |
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Post #AvUvkBa35xpJrzfXM0 by [email protected] |
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The worst case scenario here are back to back bus transfers - a clock cycle at … |
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Post #AvUvkByrbhfz6xHM24 by [email protected] |
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Here's a gist of the code that sets up the timer on the Arduino Giga.I swit… |
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Post #AvUvkU8O71zRPhsDNQ by [email protected] |
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@gloriouscow I just got a flash back to last week where I watched https://www.y… |
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Post #AvUvkUF7hzNTkb1asK by [email protected] |
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@krono Ben's a legend! |
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Post #AvUvkawEobQkW3F6uW by [email protected] |
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@gloriouscow True. |
