AN2131-DK001 Cypress Semiconductor Corp, AN2131-DK001 Datasheet - Page 190

• Manufacturer Part Number: AN2131-DK001
• Description: KIT EZ-USB DEVELOPMENT BOARD
• Manufacturer: Cypress Semiconductor Corp

Specifications of AN2131-DK001

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1333

The 8051 code responds to the SUSPEND interrupt by taking the following steps:
These actions put the EZ-USB chip into a low-power mode, as required by the USB Spec-
ification.
EZ-USB TRM v1.9
11.3
1. Performs any necessary housekeeping such as shutting off external power-con-
2. Sets bit 0 of the PCON SFR (Special Function Register). This has two effects:
suming devices.
•
•
Resume
The 8051 enters its idle mode, which is exited by any interrupt.
The 8051 sends an internal signal to the EZ-USB core which causes it to turn
off the oscillator and PLL.
WAKEUP# pin
USB Resume
Figure 11-3. EZ-USB Resume Sequence
Chapter 11. EZ-USB Power Management
Restart
Delay
Resume INT
START
Oscillator
12 MHz
48 MHz
div by
8051
PLL
2
CLK24
(USBCS.0)
Resume
Signal
Page 11-3