You can re-generate ATM PIN multiple times, but it is advisable to avoid frequent resets for security reasons.
A registered mobile number is mandatory to authenticate OTPs for PIN generation or reset.
You can use InstaServices, NetBanking, Mobile Banking, PhoneBanking, or WhatsApp/MyCards for Debit Card PIN creation without needing to visit an ATM.
Instantly Generate or Reset Your HDFC Bank Debit Card PIN Now!