2012-07-16, 16:52
For a chunk of change, you can design your own ARM SoC, and have it stamped out ad nausium by any of the block fabs, you can even do it without a block fab by using FPGA...
The construct is block based, with the CPU tied to other "married" devices on the SoC by the AMBA or Advanced Microcontroller Bus Architecture.
AMBA has 3 distinct parts, or interface classes...
1). Advanced eXtensible Interface (AXI)
2). Advanced High-performance Bus (AHB)
3). Advanced Peripheral Bus (APB)
Through these "buses" the CPU can directly address the secondary devices, or be addressed as a slave device, without much effort...
On some of the NXP devices I have worked on there is an AHB device called "DOLFIN" that does Mpeg 4, and Mpeg 2 decoding, through a simulated TSIN interface.
To send data to the DFN (Dolfin driver class) you set a pointer to a memory address that was 32 PS or TS packets in size (depending the source it was 188 or 127 bytes per packet)
Then you cleared the RDY flag, and passed the pointer address to APB.
I'm getting past my point...
Each SoC designer sets a different bus address for the AMBA bus partners, and even some of the passable registers are ordered differently, to accomplish much of the same tasks...
Examples of some devices that can be placed on the AMBA buses are as follows...
SATA controller
Ethernet controller
SDIO/MMC controller
Radio interface (Cellphone)
Serial port or UART
Thermal sensors
I2C controller
Watchdog controller
GPU
VPU
Media Controller
Sound Architecture devices (Recording and playback)
Tuners or Tuner interfaces (For Set top boxes)
Power Management controllers
Extensible memory interfaces
MTD devices (NAND / NOR flash devices)
The list goes on...
Needless to say, without the specifications for the EXACT device you are designing for, it is near impossible to know WHERE or WHAT device is there without the underlying operating system having intimate knowledge of them.
In the case of Allwinner, there is no accelerated display driver (I say it this way to simplify) and there is not a working Video decoder library for the VPU (the part responsible for decoding Video streams).
There is alot of work behind the scenes to get these things working on par with what is necessary to allow XBMC to work, Tom Cubie is smashing his head against a wall trying to get us what we need, and it will benefit more than just the XBMC community, it will benefit everyone who intends to put their software on the Allwinner A1X devices.
I hope this post was informative, and helped clear up any misconceptions...
The construct is block based, with the CPU tied to other "married" devices on the SoC by the AMBA or Advanced Microcontroller Bus Architecture.
AMBA has 3 distinct parts, or interface classes...
1). Advanced eXtensible Interface (AXI)
2). Advanced High-performance Bus (AHB)
3). Advanced Peripheral Bus (APB)
Through these "buses" the CPU can directly address the secondary devices, or be addressed as a slave device, without much effort...
On some of the NXP devices I have worked on there is an AHB device called "DOLFIN" that does Mpeg 4, and Mpeg 2 decoding, through a simulated TSIN interface.
To send data to the DFN (Dolfin driver class) you set a pointer to a memory address that was 32 PS or TS packets in size (depending the source it was 188 or 127 bytes per packet)
Then you cleared the RDY flag, and passed the pointer address to APB.
I'm getting past my point...
Each SoC designer sets a different bus address for the AMBA bus partners, and even some of the passable registers are ordered differently, to accomplish much of the same tasks...
Examples of some devices that can be placed on the AMBA buses are as follows...
SATA controller
Ethernet controller
SDIO/MMC controller
Radio interface (Cellphone)
Serial port or UART
Thermal sensors
I2C controller
Watchdog controller
GPU
VPU
Media Controller
Sound Architecture devices (Recording and playback)
Tuners or Tuner interfaces (For Set top boxes)
Power Management controllers
Extensible memory interfaces
MTD devices (NAND / NOR flash devices)
The list goes on...
Needless to say, without the specifications for the EXACT device you are designing for, it is near impossible to know WHERE or WHAT device is there without the underlying operating system having intimate knowledge of them.
In the case of Allwinner, there is no accelerated display driver (I say it this way to simplify) and there is not a working Video decoder library for the VPU (the part responsible for decoding Video streams).
There is alot of work behind the scenes to get these things working on par with what is necessary to allow XBMC to work, Tom Cubie is smashing his head against a wall trying to get us what we need, and it will benefit more than just the XBMC community, it will benefit everyone who intends to put their software on the Allwinner A1X devices.
I hope this post was informative, and helped clear up any misconceptions...
