AT43USB320A_04 ATMEL [ATMEL Corporation], AT43USB320A_04 Datasheet - Page 97

• Manufacturer Part Number: AT43USB320A_04
• Description: Full-speed USB Microcontroller with an Embedded Hub
• Manufacturer: ATMEL [ATMEL Corporation]

Selective Suspend
and Resume
Suspend and Resume
Process
Global Suspend
Global Resume
1443E–USB–4/04
rupt to the microcontroller. The microcontroller starts executing where it left off and services
the interrupt. As part of the ISR, the firmware clears the GLB SUSP bit.
At completion of RESUME signaling, the USB hardware sets the Port Suspend Status Change
bits of the Hub Port Status Change Registers.
See “Hub Port Control Register – HPCON” on page 89.
The Host stops sending packets, the hardware detects this as global suspend signaling and
stops all downstream signaling. Finally, the hardware asserts the GLB_SUSP interrupt.
The Host resumes signaling, the hardware detects this as global resume and propagates this
signaling to all downstream ports. Finally, the hardware enables the oscillator and asserts the
RSM interrupt.
2. Global suspend signaling detected
3. Stop downstream signaling
4. Set GBL SUS bit → interrupt
10. SLEEP bit detected
11. Shut off oscillator
2. Resume signaling detected
3. Propagate signaling downstream
4. Enable oscillator
5. Set RSM bit → interrupt
Hardware
Hardware
1.Host stops sending packets
1.Host resumes signaling
5. Shut down any peripheral activity
6. Set Sleep Enable and Sleep Mode bits
7. Set GPIO to low power state if required
8. Set UOVCER bit 2
9. Execute SLEEP instruction
6. Reset RSM and GBL SUSP bits
7. Restore GPIO states if required
8. Clear UOVCER bit 2
9. Enable peripheral activity
of MCUCR
Firmware
Firmware
AT43USB320A
97