How fast can I drive the SX????

pmullin

Hello All,

I am using the SX chip as the timing brain behind a high frequency induction heater. This·application will provide alternating pulses (rb0 on rb1 off, then rb0 off and rb1 on) that drive a DC inverter circuit. Using an RTCC interrupt loop, the fastest I have been able to drive the chip is 140 KHz. My target frequency is 200 KHz. While I have come close, I am not certain that I have exploited all of this chips potential. Has anybody explored similar applications? Any advise would be greatly appreciated.

Thanks ... Patrick

Current code attached ...

Bean

Instead of clearing RTCC you should use the RETIW instruction.

For 75MHz there isn't a value to get exactly 200KHz, but 187 will get you (75 Mhz / 187) / 2=200534.76 Hz

remove CLR RTCC

replace RETI with

MOV W,#-187 ' NOTE MINUS SIGN
RETIW


If you used 50MHz and -125 you would get exactly 200Khz and wouldn't be driving the SX so hard.

Bean.

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pmullin

Thanks Bean,

I'll put this into action and let you know how it worked out.



Take care ... Patrick