9V NiMH charger

I have spare ports (CCP / ADC) on my pic16F913 and i was thinking to use them to charge the NiMH battery (Energizer NH22-175 "9V" / 175mAh) http://data.energizer.com/PDFs/nh22-175.pdf.

Following the Microchip AN960 (http://ww1.microchip.com/downloads/e...tes/00960a.pdf) and Panasonic (http://http://www.panasonic.com/indu...rgemethods.pdf) i draw the charging flowchart:
...see the atachment

...so, the battery have to be charged in 3 modes :
-transition charge current = 44mA
-fast charge current = 175mA
-trickle charge current = 8mA

I found this circuit http://www.angelfire.com/electronic/...es/figure3.gif on the internet but i have hard time to understand it (change it)... please help.

Thank you.