Are these counters mapped to the memory locations specified in the manual (21440 Datasheet Rev 2.0, Mar 2000)? The manual gives per-counter offsets. Then it says that these offsets are relative to either 0x100 or 0x200. If they are read at 0x100 the counters are reset. Regardless of where I read them or how often I read them, I always get back the number "1" for all counters. I am reading them as 32-bit quantities. I am using the following as the per-port absolute CSR offsets: static uint32 Port_CSR_Addrs[] = { 0x38400000, 0x38401000, 0x38402000, 0x38403000, 0x38404000, 0x38405000, 0x38406000, 0x38407000, }; I was hoping to use them to further diagnose my previously mentioned problem. Thanks, Tammo