Microchip USB4624 Handleiding


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2013 Microchip Technology Inc. DS00001589A-page 1
INTRODUCTION
The Microchip USB253x/USB46x4/USB3x13 product lines are a family of feature-rich, low-power USB 2.0 hubs
optimized for use in portable devices or embedded systems where high performance and minimal BOM costs are critical
design requirements. The SMBus slave interface is a 2-pin protocol which can be used to customize the functionality of
this family of USB hubs. The System on Chip (SoC) can use this interface to control the digital and USB lines for testing,
configure custom functionality, and load custom firmware to unlock the various features of the embedded processor.
Among these features is a USB compliance test mode designed to facilitate USB compliance testing when a USB253x/
USB46x4/USB3x13 hub is applied within an embedded system.
This document includes the following topics:
Embedded Host Compliance Testing Modes Overview
Test Mode Setup
Test Mode Descriptions
Audience
This document is written for developers who are familiar with USB and SMBus protocols as well as USB 2.0 compliance
tests. The goal of this application note is to describe the USB253x/USB46x4/USB3x13 embedded test modes to help
facilitate compliance testing within embedded designs.
EMBEDDED HOST COMPLIANCE TESTING MODES OVERVIEW
The “Embedded Host Compliance Testing Modes” feature is designed to allow the hub to be tested for USB compliance
when the tester is unable to easily control testing modes through the upstream USB port. These test modes are enabled
and controlled via a series of SMBus writes to the hub that are performed during configuration. After the test modes
have been enabled during configuration, the hub can generate one of the following test patterns through any of its down-
stream ports:
TEST_SE0: The hub’s downstream port drives SE0
TEST_J: The hub’s downstream port enters high-speed J state
TEST_K: The hub’s downstream port enters high-speed K state
TEST_PACKET: The hub’s downstream port sends compliance test packets
TEST MODE SETUP
The following configuration steps must be performed to activate the “Embedded Host Compliance Testing Modes”.
Refer to Application Note 26.18 entitled “SMBus Slave Interface for the USB253x/USB3x13/USB46x4” for in-depth
information regarding the SMBus protocol as well as additional features that can be controlled via SMBus.
1. Pull-up the SMBus SCL and SDA lines to 3.3V and reset the hub to hold the device in the SoC configuration
stage.
2. Using SMBus slave address 2D, write to the following test configuration register to select the desired test mode.
AN1589
USB253x/USB46x4/USB3x13 Embedded Testing
Modes
Author: Andrew Rogers,
Microchip Technology Inc.
DS00001589A-page 2 2013 Microchip Technology Inc.
AN1589
3. Using SMBus slave address 2D, write to the following port configuration register to select the desired
downstream USB test port.
4. The selected test pattern will now be generated through the selected downstream port. The USB attachment
command is not required. The device will exit test mode when reset.
TABLE 1: CNTLP REGISTER (0x318C)
BIT NAME DESCRIPTION
7:6 Reserved Always ‘0’
3:1 EMBEDTEST[2:0] (000) - Default Operation - no test mode asserted
(001) - TEST_SE0 - hub enters high-speed receive and drives
SE0 on the hub’s downstream port
(010) - TEST_J - hub’s downstream port enters high-speed J
state
(011) - TEST_K - hub’s downstream port enters high-speed K
state
(100) - TEST_PACKET - send test packets on downstream port
All others Reserved
0 Reserved Always ‘0’
TABLE 2: COM_TEST_PSEL REGISTER (0x600F)
BIT NAME DESCRIPTION
7 Reserved Always ‘0’
6:4 SIG_GROUP[2:0] Not used for this application. Default (000)
3:0 PORT_SEL[3:0] (0000) - Upstream Port
(0001) - Downstream Port 1
(0010) - Downstream Port 2
(0011) - Downstream Port 3
(0101) - Downstream Port 4
(0101) - Not Used
(0110) - Not Used
(0111) - Not Used
(1000) - Common Block
2013 Microchip Technology Inc. DS00001589A-page 3
AN1589
TEST MODE DESCRIPTIONS
This section describes each test mode behavior. Screen captures of the four test modes are included to show what to
expect when operating in each test mode. These oscilloscope screen images were captured from a USB4624 hub with
probes connected to the D+ and D- pins on the selected downstream port.
TEST_SE0
This mode drives a single-ended zero (SE0, both D- and D+ pins low) on the selected port.
To enable TEST_SE0 on Downstream Port 1:
Write 0x02 to configuration register 0x318C
Write 0x01 to configuration register 0x600F
TEST_J
The TEST_J pattern asserts and holds the D+ pin high until the part is reset or the CNTLP register is modified. The
magnitude of the D+ signal can be measured with respect to ground to verify compliance.
FIGURE 1: TEST_J WAVEFORM
To enable TEST_J on Downstream Port 1:
Write 0x04 to configuration register 0x318C
Write 0x01 to configuration register 0x600F


Product specificaties

Merk: Microchip
Categorie: Niet gecategoriseerd
Model: USB4624

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