MCIMX281AVM4B Freescale Semiconductor, MCIMX281AVM4B Datasheet - Page 1810

• 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

Switch Configuration
Ethernet
Ethernet
Port 0
Port 1
ENET-MAC 0
ENET-MAC 1
Switch
Register
Rx
Map
Buffer
"1"
DMA0
Figure 29-4. Switch Mode Configuration Overview
29.3.4 Port 0 Input Buffer
A dedicated input buffer of at least 2 Kbyte storage is implemented at the port0 (DMA0)
input interface, when the switch is operating in switch mode. In bypass mode, this buffer
is bypassed.
The input buffer is normally operated in store&forward mode of operation, absorbing a
DMA burst and forwarding the frame to the switch (internally) when the complete frame
has been stored in the input buffer.
However, to allow for jumbo-frame support, the input buffer can be operated in cut-through
mode (see register MODE_CONFIG). In cut-through mode, a frame is forwarded to the
switch internal input, when the buffer has reached a fill level as 1536 bytes (192 words).
If a frame of less than this threshold is written by DMA0, it is forwarded as in store&forward
with all options (ff_tx_xxx). If a frame larger than this threshold is written, then the input
buffer will start forwarding the frame to the switch, when the threshold is reached. It is then
expected that DMA0 guarantees writing data fast enough to avoid a buffer underflow.
When the input buffer is operating in cut-through mode, the additional transmit options
(ff_tx_crc_fwd0, ff_tx_ipchk_ins0, ff_tx_protchk_ins0, ff_tx_ts_frm0) can be used only
for frames not exceeding the cut-through threshold. Frames exceeding the threshold cannot
use these functions and they must be set to 0 (and they will operate as defined for 0
accordingly).
i.MX28 Applications Processor Reference Manual, Rev. 1, 2010
1810
Freescale Semiconductor, Inc.