Difference between revisions of "The Undocumented Pi"

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==PMIC==
 
==PMIC==
  
Recent boards contain a MaxLinear XR77004, which looks like a stripped down version of MxL7704 ([https://www.maxlinear.com/ds/mxl7704.pdf datasheet]). It is on the system I²C bus (I2C8 on RPi4, I2C0 on all other devices) at address 0x1d. No documentation is available.
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The BCM2835 chip has an on-chip SMPS and an LDO for the LPDDR2 memory chip. RPi2 and RPi3 B use custom circuitry made of discrete components to do the power-up sequencing, including an NCP6343 chip ([https://www.onsemi.com/products/power-management/dc-dc-controllers-converters-regulators/converters/ncp6343 datasheet]) at I²C address 0x1c. The RPi 3B+ and RPi 4B boards contain a MaxLinear MxL7704 ([https://www.maxlinear.com/ds/mxl7704.pdf datasheet]) at address 0x1d.
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The PMIC is always on the system I²C bus (I2C8 on RPi4, I2C0 on all other devices).
  
 
=Boot ROM=
 
=Boot ROM=

Revision as of 11:44, 2 March 2020

Back to the Hub.


Resources:

Hardware & Peripherals:

Hardware and Hardware History.

Low-level Peripherals and Expansion Boards.

Screens, Cases and Other Peripherals.

Software & OS Distributions:

Software and Distributions

Documentation:

Documentation Page

The Undocumented Pi

Hardware

SoC

There is a nicely ordered table with all BCM2835_registers as found in the GPU code published by Broadcom. Unfortunately, the table does not quite match the SoC in the Raspberry Pi, but it's a good start. The sections below should serve as a companion to that table.

BCM2711

The BCM2711 does not have PLLH.

PMIC

The BCM2835 chip has an on-chip SMPS and an LDO for the LPDDR2 memory chip. RPi2 and RPi3 B use custom circuitry made of discrete components to do the power-up sequencing, including an NCP6343 chip (datasheet) at I²C address 0x1c. The RPi 3B+ and RPi 4B boards contain a MaxLinear MxL7704 (datasheet) at address 0x1d.

The PMIC is always on the system I²C bus (I2C8 on RPi4, I2C0 on all other devices).

Boot ROM

Firmware

Abbreviations

CM
Clock Manager
HSM
HDMI State Machine
OTP
One-Time Programmable (memory)