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phil11
01-21-2009, 08:03 AM
Taking advantage of the PLLX16 feature, is it possible to send a square wave in the 20 MHz range as an output? If so, would the program have to be written in assembly? Using a fairly simple Spin program, I don't get a signal if I try to send something at a speedˇfaster than 400 clock cycles (around 50KHz) using "XTAL1 + pll16x". I need a high speed signal to control a TLC5947 LED Driver.

Mike Green
01-21-2009, 08:16 AM
If you want to generate a square wave, you can do that up to about 160MHz in Spin by using the "cog counters".ˇ Download the application note on this (AN001) from the Propeller downloads page.ˇ It includes some documentation and sample code for generating a square wave at different frequencies.

If you want to "do something" more complex at high speed, you can do it in Spin up to about 20KHz, but you'll need assembly for higher frequencies.ˇ For example, the Propeller can do asynchronous serial half duplex I/O at 19KBaud with one cog in Spin and full duplex in assembly up to around 230KBaud.