AN2136SC Cypress Semiconductor Corp, AN2136SC Datasheet - Page 188

• Manufacturer Part Number: AN2136SC
• Description: IC MCU 8051 8K RAM 24MHZ 44QFP
• Manufacturer: Cypress Semiconductor Corp
• Series: EZ-USB®r

Specifications of AN2136SC

• Applications: USB Microcontroller
• Core Processor: 8051
• Program Memory Type: ROMless
• Controller Series: AN213x
• Ram Size: 8K x 8
• Interface: I²C, USB
• Number Of I /o: 8
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 44-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1309

11 EZ-USB Power Management
11.1
Introduction
The USB host can suspend a device to put it into a power-down mode. When the USB
signals a SUSPEND operation, the EZ-USB chip goes through a sequence of steps to
allow the 8051 to first turn off external power-consuming subsystems, and then enter an
ultra-low-power mode by turning off its oscillator. Once suspended, the EZ-USB chip is
awakened either by resumption of USB bus activity, or by assertion of its WAKEUP# pin.
This chapter describes the suspend-resume mechanism.
12 MHz
WAKEUP pin
START
USB Resume
Oscillator
STOP
PLL
48 MHz
Restart
Delay
div by
2
CLK24
PCON.0
Signal
Resume INT
8051
Resume
(USBCS.0)
USB
No USB activity
"SUSPEND"
for 3 msec.
Interrupt
Figure 11-1. Suspend-Resume Control
Figure 11-1 illustrates the EZ-USB logic that implements USB suspend and resume.
These operations are explained in the next sections.
EZ-USB TRM v1.9
Chapter 11. EZ-USB Power Management
Page 11-1