AT43USB320A-AC Atmel, AT43USB320A-AC Datasheet - Page 95

• Manufacturer Part Number: AT43USB320A-AC
• Description: IC USB MCU EMBED HUB AVR 100LQFP
• Manufacturer: Atmel
• Series: AVR®r

Specifications of AT43USB320A-AC

• Applications: USB Hub/Microcontroller
• Core Processor: AVR
• Controller Series: AT43USB
• Ram Size: 512 x 8
• Interface: SPI Serial, USB, UART
• Number Of I /o: 32
• Voltage - Supply: 4.4 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 100-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Program Memory Type: -

Hub and Port Power
Management
Overcurrent sensing
Port Power Switching
1443E–USB–4/04
• Bit 1 – PESC: Port Enable/Disable Status Change
0 = No change has occurred on Port Enable/Disable Status
1 = Port Enable/Disable status has changed
Set by hardware due to babble, physical disconnect or overcurrent except for Port 5 in which
case it is set by hardware at EOF2 due to hardware events. Cleared by firmware via Host
request ClearPortFeature(PORT_ENABLE).
• Bit 0 – PCSC: Port Connect Status Change
0 = No change has occurred on Current Connect Status
1 = Current Connect Status has changed
This bit is set by hardware at EOF2 after it detects a connect or disconnect at a port, except for
Port 5. Hardware sets this bit for Port 5 after a hub reset. Cleared by firmware via Host request
ClearPortFeature(PORT_CONNECTION).
For the utmost flexibility, the USB hardware of the AT43USB320A is designed to accommo-
date hubs of various capacitance. Management of the downstream port power is also defined
by the firmware: per port or global overcurrent sensing, individual or gang power switching.
While the interface to the external power supply monitoring and switching is achieved through
the microcontroller’s GPIO pins, the USB hardware of the AT43USB320A contains the cir-
cuitry to handle all the possible combinations port power management tasks.
1. Global Overcurrent Protection – In this mode, the Port Overcurrent Indicator and
2. Individual Port Over-current Protection – The Hub Overcurrent Indicator and Hub
1. Gang Power Switching – One of the microcontroller I/O port pins must be pro-
2. Individual Power Switching – One microcontroller I/O port pin must be assigned for
3. Multiple Ganged Overcurrent Protection – Overcurrent sensing is grouped physi-
Figure 22 shows a simplified diagram of a power management circuit of an AT43USB320A
based hub design with global overcurrent protection and ganged power switching.
Port Overcurrent Indicator Change should be set to 0's. For the AT43USB320A an
external solid state switch, such as the Micrel MIC2545-2, is required to switch power
to the external USB ports. The FLG# output of the switch should be connected to PD0.
When an overcurrent occurs, FLG is asserted and the firmware should set the Hub
Overcurrent Indicator and Hub Overcurrent Indicator Change and switch off power to
the hub.
Overcurrent Indicator Change bits should be set to 0's. One MIC2026-2 is required for
each two USB ports. Each of the FLG# outputs of the MIC2026-2 should be connected
to an unused microcontroller port. An overcurrent is indicated by assertion of FLG#.
The firmware sets the corresponding port's Overcurrent Indicator and the Overcurrent
Indicator Change bits and switches off power to the port. At the next IN token from the
Host, the AT43USB320A reports the status change.
grammed as an output to control the external switch, PWRN. Switch ON is requested
by the USB Host through the SetPortFeature(PORT_POWER) request. Switch OFF is
executed upon receipt of a ClearPortFeature(PORT_POWER) or upon detecting an
overcurrent condition. The firmware clears the Power Control Bit. Only if all of the
Power Control Bits of ports 1 through 4 are cleared should the firmware de-assert the
PWRN pin.
each USB port to control the external switch, PWRxN, where x = 1, 2, 3, 4. Each of the
Power Control Bits controls one PWRxN.
cally into one or more gangs, but reported individually.
AT43USB320A
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