US Patent 7966445 Read status controller

A controller in a processing system can detect programmable bit sequences sent from a host processor to an external device, such as a memory, indicating whether a response from the external device needs to be read. The controller can also read a response from the external device and act appropriately, e.g., determine if an error has occurred by comparing the device's actual response to one or more programmably determined responses. Upon reading a particular response, e.g., a response indicating an error, the controller can issue an interrupt request to the host processor for further action. The controller can also track which external device access caused a particular response to occur.