The HID shim is a bridge between the controller and an interface device. The resulting interface can be used to exchange commands and status with the controller. The HID shim is only present in certain controller configurations. When present, it exports access to the Status Interface and Error Injection Interface through the use of Vivado logic analyzer. When absent, the Status Interface and Error Injection Interface are only accessible through I/O pins.
If desired, the Status Interface and Error Injection Interface can be connected in other ways. These interfaces are easy to disconnect from the HID shim or I/O Pins and reconnect to other logic, such as register files or finite state machines. See the Status interface section and Error Injection section.