There is provided a communication apparatus. A communication unit transmits data to a communication module, which communicates with an external device, according to a clock signal, and receives data from the communication module in accordance with a timing corresponding to a timing signal generated by delaying the clock signal. An adjustment unit adjusts an amount of the delay. A control unit controls the communication unit to repeatedly perform first processing for transmitting a first command to the communication module, second processing for receiving a first response that is sent from the communication module, and third processing for transmitting a packet to the communication module according to the first response. In a predetermined mode, the control unit controls the communication unit to perform processing for transmitting data of the packet regardless of contents of the first response.