Difference between revisions of "The Undocumented Pi"
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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. | 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. | ||
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| + | ===BCM283x=== | ||
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| + | There is a VCE block to accelerate video encoding/decoding. No documentation AFAIK. | ||
===BCM2711=== | ===BCM2711=== | ||
The BCM2711 does not have PLLH. | The BCM2711 does not have PLLH. | ||
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| + | The VCE block was apparently removed, but there is now a HEVC block. | ||
==PMIC== | ==PMIC== | ||
Revision as of 11:48, 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:
Documentation:
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.
BCM283x
There is a VCE block to accelerate video encoding/decoding. No documentation AFAIK.
BCM2711
The BCM2711 does not have PLLH.
The VCE block was apparently removed, but there is now a HEVC block.
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).
See also this very informative blog post by James Adams.
Boot ROM
Firmware
Abbreviations
- CM
- Clock Manager
- HSM
- HDMI State Machine
- OTP
- One-Time Programmable (memory)
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