An imaginary device controller can supply a connected device with a data rate of 115200 bit / s.
If it reaches the low watermark, it triggers an interrupt so that the responsible process is woken up and new data is sent to the controller. Waking up the process including refilling the queue in the controller always takes 2200 μs for simplicity. The controller uses double buffering, i.e. That is, the refilling process can write to one buffer while the device controller reads data from a second buffer. Only when this buffer is empty is a switchover to the other buffer. The duration of the switchover can be neglected in the calculation.
What is the effective data rate (in bit / s) to the connected device in the following cases?
A) Size of the buffer: 1 byte. Low watermark: 0 bytes.
B) Size of the buffer: 80 bytes. Low watermark: 0 bytes.
C) Size of the buffer: 1200 bytes. Low watermark: 16 bytes
D) How should the low watermark be selected so that the net data rate of the device is achieved in terms of computing power?
I also need the calculation steps