AM335xHardwareDesignGuide
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AM335x Hardware Design Guide
== Hardware Design Timeline → ==
Constructing the Block Diagram | → | Selecting the Boot Mode | → | Confirming Pin Multiplexing Compatibility | → | Confirming Electrical and Timing Compatibility 潸然泪下造句 | → | Designing the Power Subsystem | → | Designing the Clocking Subsystem | → | 介绍家乡Floorplanning the PCB | → | Creating the Schematics | → | Laying out the PCB | → | Testing / Debugging |
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Introduction
Welcome to the Hardware Design Guide. The purpo of this guide is to walk hardware designers through the various stages of designing a board on this platform. The guide follows the structure shown in the Hardware Design Timeline above. Each design stage in t
he Timeline links to a collection of uful documentation, application notes, and design recommendations pertaining to that stage. Using this Guide, hardware designers can efficiently locate the resources they need at every step in the board design flow.
Constructing the Block Diagram
The first step in designing the hardware platform is to create a detailed block diagram. The block diagram should contain all major system ICs and illustrate which I/O ports are ud for device interconnection. Below is a collection of resources to aid in the Block Diagram creation process.
∙The TMDXEVM3358 EVM is always a good source from which to start building a reference design for the devices. The technical documentation for the EVM is available.
∙The links at the TI website below provide block diagrams, application notes, tools, software, design considerations, and other related information for various products under category "Related End Equipments".
oAM335x Product Folder
∙Select from a list of complementary devices to attach to AM335x device in your system:
oPower Management Devices refer link
Selecting the Boot Mode
The block diagram should also indicate which interface will be ud for booting this device.
∙The devices contain an on-chip ROM Bootloader:
oThe boot config pins are sampled at power-on-ret
oSets up system for boot depending on boot configuration lected
oDepending on boot mode, copies image to internal RAM and then executes it
o毛笔怎么选Maximum size of the boot image is 128KBytes
发现人才∙The following boot modes are supported:
oNOR Flash boot
oNAND Flash boot
oSPI boot
oSD/MMC boot
oEMAC boot
oUART boot
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oUSB boot (like an ethernet card, not as mass storage)
∙If the first boot source fails to boot, the ROM will move on to the next one in the quence. Keep in mind that some boot sources take some time to timeout if that boot source isn't available.
∙Read AM335x Technical Reference Manual地球的宇宙环境 Initialization Chapter to understand details on different boot modes
∙Key Boot Considerations:
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oIt is recommended to include population options for other boot modes to aid in development
oBoot pins have other functions after ret. Make sure your board design takes this into account when choosing pullup/down resistors for the boot pins.
Confirming Pin Multiplexing Compatibility
The AM335x device contains many peripheral interfaces. In order to reduce package costs while maintaining maximum functionality, many Approximately half of the AM335x terminals can multiplex up to eight signal functions. Although there are many combinations of pin-multiplexing that are possible, only a certain number of ts , called IO ts, are valid due to timing limitations. The valid IO ts were carefully chon to pr
ovide many possible application scenarios for the ur.
Texas Instruments has developed a Windows application called Pin Mux Utility that helps a system designer lect the appropriate pin-multiplexing configuration for their AM335x bad product design. This tool provides a way to lect valid IO Sets of specific peripheral interfaces to insure the pin-multiplexing configuration lected for a design only us valid IO Sets supported by AM335x.
∙Pin Mux Utility
Confirming Electrical and Timing Compatibility
A key step in the hardware design before beginning schematic capture is to confirm both DC and AC electrical compatibility between this device and the other ICs connected to it.
∙The device datasheet has important information with regards to timing and electrical characteristics.
∙For High Speed Interfaces you can run IBIS simulations using IBIS models provided for AM335x ZCE and ZCZ package to confirm signal Integrity.
oZCE Package IBIS
oZCZ Package IBIS
∙Using IBIS Models for Timing Analysis
∙Note: TI provides PCB layout specifications for the following interfaces, eliminating the need to perform electrical analysis:
olpDDR/DDR2/DDR3
Designing the Power Subsystem
Once the block diagram has been validated for pin multiplexing, electrical, and timing compatibility, the power sub-system can be designed. See the below resources on estimating power consumption and designing a matching power subsystem.
