Socrom 820-01598

[Dark_]

Hello everyone,

I wanted to ask a question, but I have not been able to find information on why this, I am somewhat new looking for faults in macbook and I have come across this part of the schematic card in the image appears Board ID and a series of resistors in PULL-UP to the rail PP1V8_AWAKE, R4710,R4711 and R4712 go MISO, MOSI and CLK of this eeprom U4770 to T2, but on the board are not installed and seeing the schematic part that says BOARD ID.
I don't understand why they are missing being pull ups for this EEPROM. Does anyone know why ?

Thank you very much!

[mon2]

Just a logical stab at your raised question

1) spi is a push-pull style of interface so pull ups are not required since the signal lines are never floating.

2) most likely the same lines serve as a board ID cluster of pins on power up and afterwards become spi pins. By default there are probably internal weak pull downs and if needed external resistors will change their logic states.

[Dark_]

ohh very thanks for the clarification