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USB3613 数据表(PDF) 22 Page - Microchip Technology |
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USB3613 数据表(HTML) 22 Page - Microchip Technology |
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22 / 57 page ![]() USB 2.0 Hi-Speed 3-Port Hub Controller Optimized for Portable Applications Datasheet DS00001714A-page 22 2014 Microchip Technology Inc. signature of “2DFU” (device firmware upgrade) beginning at address 0xFFFA. If a valid signature is found, then the external ROM is enabled and the code execution begins at address 0x0000 in the external SPI device. If a valid signature is not found, then execution continues from internal ROM. SPI ROMs used with the device must be 1 Mbit and support either 30 MHz or 60 MHz. The frequency used is set using the SPI_SPD_SEL configuration strap. Both 1- and 2-bit SPI operation is supported. For optimum throughput, a 2-bit SPI ROM is recommended. Both mode 0 and mode 3 SPI ROMS are also supported. Refer to Section 6.3.1, "SPI Speed Select (SPI_SPD_SEL)," on page 27 for additional information on selection of the SPI speed.For all other configurations, the firmware checks for the presence of an external I2C/SMBus. It does this by asserting two pull down resistors on the data and clock lines of the bus. The pull downs are typically 50Kohm. If there are 10Kohm pull-ups present, the device becomes aware of the presence of an external SMBus/I2C bus. If a bus is detected, the firmware transitions to the SOC_CFG state. 5.1.6 SOC Configuration Stage (SOC_CFG) In this stage, the SOC may modify any of the default configuration settings specified in the integrated ROM such as USB device descriptors, or port electrical settings, and control features such as upstream battery charging detection. There is no time limit. In this stage the firmware will wait indefinitely for the SMBus/I2C configuration. When the SOC has completed configuring the device, it must write to register 0xFF to end the configuration. 5.1.7 Configuration Stage (CONFIG) Once the SOC has indicated that it is done with configuration, then all the configuration data is combined. The default data, the SOC configuration data, the OTP data are all combined in the firmware and device is programmed. After the device is fully configured, it will go idle and then into suspend if there is no VBUS or Hub.Connect present. Once VBUS is present, and upstream battery charging is enabled, the device will transition to the Battery Charger Detection Stage (CHGDET). If VBUS is present, and upstream battery charging is not enabled, the device will transitions to the Connect (Hub.Connect) stage. 5.1.8 Battery Charger Detection Stage (CHGDET) After configuration, if enabled, the device enters the Battery Charger Detection Stage. If the battery charger detection feature was disabled during the CONFIG stage, or the HUB_CONN pin is asserted, the device will immediately transition to the Hub Connect (Hub.Connect) stage. If the battery charger detection feature remains enabled, the battery charger detection sequence is started automatically. If a charger is detected during this stage, the device asserts the CHRGDET[1:0] output pin function if the charger type identified is not masked. If the charger detection remains enabled, the device will transition to the Hub.Connect stage if using the hardware detection mechanism. 5.1.9 Hub Connect Stage (Hub.Connect) Once the CHGDET stage is completed, the device enters the Hub.Connect stage. USB connect can be initiated by asserting the HUB_CONN pin high. The device will remain in the Hub.Connect stage indefinitely until the HUB_CONN pin is deasserted. 5.1.10 Normal Mode Lastly the SOC enters the Normal Mode of operation. In this stage, full USB operation is supported under control of the USB Host on the upstream port. The device will remain in the normal mode until the operating mode is changed by the system. |
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