MCIMX281AVM4B Freescale Semiconductor, MCIMX281AVM4B Datasheet - Page 2034

• Manufacturer Part Number: MCIMX281AVM4B
• Description: IC MPU I.MX28 1.2 289MAPBGA
• Manufacturer: Freescale Semiconductor
• Series: i.MX28r

Specifications of MCIMX281AVM4B

• Core Processor: ARM9
• Core Size: 32-Bit
• Speed: 454MHz
• Connectivity: CAN, EBI/EMI, Ethernet, I²C, MMC, SmartCard, SPI, SSI, UART/USART, USB OTG
• Peripherals: DMA, I²S, LCD, POR, PWM, WDT
• Program Memory Size: 128KB (32K x 32)
• Program Memory Type: Mask ROM
• Ram Size: 32K x 32
• Voltage - Supply (vcc/vdd): 1.25 V ~ 5.25 V
• Data Converters: A/D 17x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 289-LFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of I /o: -
• Eeprom Size: -
• Lead Free Status / Rohs Status: Supplier Unconfirmed

Operation
each leg of the differential pair. The envelope or squelch detector, described below, ensures
that the differential signal has sufficient magnitude to be valid. The HS differential receiver
tolerates up to 500 mV of common mode offset.
32.2.4.2 Squelch Detector
The squelch detector is a differential analog receiver and threshold comparator. Its output
is 1, if the differential magnitude is less than a nominal 100 mV threshold. Otherwise, its
output is 0. Its purpose is to invalidate the HS differential receiver when the incoming signal
is simply too low to receive reliably.
32.2.4.3 LS/FS Differential Receiver
The low-speed/full-speed differential receiver is both a differential analog receiver and
threshold comparator. The crossover voltage falls between 1.3 V and 2.0 V. Its output is 1,
when the USB_DP line is above the crossover point and the USB_DN line is below the
crossover point. The digital receiver section decodes the receiver data into J or K state
according to the speed.
32.2.4.4 HS Disconnect Detector
This host-side function is not used in i.MX28 applications, but is included to make a complete
UTMI macrocell. It is a differential analog receiver and threshold comparator. Its output is
a 1 if the differential magnitude is greater than a nominal 575-mV threshold. Its output is
0, otherwise.
32.2.4.5 USB Plugged-In Detector
The USB plugged-in detector looks for both USB_DP and USB_DN to be high. There is a
pair of large on-chip pullup resistors (200 K ) that hold both USB_DP and USB_DN high
when the USB cable is not attached. The USB plugged-in detector signals a 0 in this case.
When in device mode, the host/hub interface that is upstream from the i.MX28 contains a
15 K pulldown resistor that easily overrides the 200 K pullup. When plugged in, at least
one signal in the pair will be low, which will force the plugged-in detector's output high.
32.2.4.6 Single-Ended USB_DP Receiver
The single-ended USB_DP receiver output is high whenever the USB_DP input is above
its nominal 1.8 V threshold.
i.MX28 Applications Processor Reference Manual, Rev. 1, 2010
2034
Freescale Semiconductor, Inc.