THere are two development systems for the BQ2031 listed in the product folder:
DV2031S1 Fast Charge Development System User's Guide
DV2031S2 Lead-Acid Charger Development System Control of On-Board p-FET (Rev. B)
Which is the right one to use?
I typically have used the S1, but I believe all that is different for the S2 is the use of a P-CH FET instead of a PNP.