While testing my I2S project I ran into some boot issues on the Raspberry Pi 4 host. For what seemed to be some unknown reasons the boot process was completely chaotic, sometimes running well, sometimes hanging. I banged my head for some time looking for a solution until it came to my mind to change the power source. Suddenly all went well. So I though that there must be some current draw issue, some significant current consumption that my initial power source, an AC plug dongle that delivered only a mere 500mA, could not cope with. So I bought an USB tester, curious to find out what is the problem. This is the current consumption with Svxlink on and I2S dongle on:
A total of 517mA that the first power source was not able to deliver. This was probably the reason that RPi could not boot sometimes. However, the biggest surprise came with Svxlink off: current draw was reduced to 421mA:
It came as a shock to realize that only the Svxlink module needs 100mA, almost 20% of the total consumption RPi curremnt consumption. The digilent I2S dongle draws only 30mA. The following image shows the current draw without I2S dongle attached and with Svxlink turned off:
Now, I am aware that this cheap chinese dongle might not display an accurate value, but whatever error is there, that is present in each measurement so the order of magnitude of the values should be the same even though the actual values might be a bit off. This means that for any project that involves using Svxlink one should be very careful in what concerns power supply choice.
73
Leave a Reply