I have a requirement to generate an analog output of +/-10V that is proportional to +/- 2000 deg angle.

The angle is measured by a 360ppr encoder and interfaced with a HCTL2020 decoder, which in turn is connected to a 89c52 that displays t he angle information via a IIC 4 digit display driver on a 7 seg. LED. No problem upto this.

But now the client wants the analog output as above.

I plan to use a 12bit DAC like the AD7392, that is fed via a ripple counter like the CD4040 / CD4020 etc. The counter will be fed by the DCDR output from the HCTL2020. The problem really is to select the -ve polarity when the encoder is in the CCW segemnt and +ve polarity when in the CW segment.

One cycle of the drive will be like this : Start @0000 - rotate upto 1000 deg CW - reverse to 0000 deg - rotate to 1000 deg CCW - reverse to 0000 deg. Continue for next cycle.

As for signals to do the above I have the DCDR pulse output ( 1 pulse per deg angle) and up/dn direction from the HCTL2020 chip.

Somehow I have been thinking in a single route and have not been able to come up with an elegant solution.

Any ideas ?

Thanks so much.

Raghu