CH8Ck is a test program from PIMC that simulates invalid host conditions. When running Ch8Ck software, the EZ-USB AT2 will not fully follow the specification in response to the following invalid host behavior:
1) Invalid traffic to valid endpoints is not ignored. IN traffic to OUT endpoints and OUT traffic to IN endpoints is NAKed by the EZ-USB AT2.
2) Spurious traffic to the default pipe is not ignored. IN and OUT traffic sent to the default pipe, when a control transfer is not in progress, is NAKed.
3) Some protocol stall conditions on the default pipe are handled improperly. In particular, an attempt by the host to transfer more Data In than indicated in the Setup stage of a control transfer should result in a STALL. The EZ-USB AT2 instead ACKs the IN token.
Note: Chapter 8 testing is not required for USB Certification.