I am having trouble installing the Arduino bootloader on a ATM328PB.
I successfully did that a few months back (same project, slightly larger PCB) but this time around I am stuck.
I am using an Arduino UNO as the ISP.
I have the following connected:
MOSI → 15
MISO → 16
SCK → 17
RST → 29
as well as:
VCC → 4, 6, 18
GND → 3, 5, 21
XTAL → 7, 8
GND → 20 (via 0.1uF Cap)
VCC → 29 (via 10K Resistor)
I already have tried repeatedly with different chips and verified every single connection. I even managed to hook up an oscilloscope (see attachments).
As you can see, MOSI seems normal, as does CLK. MISO, on the other hand, presents some activity but it also is extremely weak (around 300mV pp).
Would you be able to suggest where I should look next in order to solve my problem?