LPC2468FBD208,551 NXP Semiconductors, LPC2468FBD208,551 Datasheet - Page 267

• Manufacturer Part Number: LPC2468FBD208,551
• Description: IC ARM7 MCU FLASH 512K 208-LQFP
• Manufacturer: NXP Semiconductors
• Series: LPC2400r

Specifications of LPC2468FBD208,551

• Program Memory Type: FLASH
• Program Memory Size: 512KB (512K x 8)
• Package / Case: 208-LQFP
• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 72MHz
• Connectivity: CAN, EBI/EMI, Ethernet, I²C, Microwire, MMC, SPI, SSI, SSP, UART/USART, USB OTG
• Peripherals: Brown-out Detect/Reset, DMA, I²S, POR, PWM, WDT
• Number Of I /o: 160
• Ram Size: 98K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 8x10b; D/A 1x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: LPC24
• Core: ARM7TDMI-S
• Data Bus Width: 16 bit, 32 bit
• Data Ram Size: 98 KB
• Interface Type: CAN/I2S/ISP/SSP/UART/USB
• Maximum Clock Frequency: 72 MHz
• Number Of Programmable I/os: 160
• Number Of Timers: 6
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: MDK-ARM, RL-ARM, ULINK2, IRD-LPC2468-DEV, SAB-TFBGA208, KSK-LPC2468-PL
• Development Tools By Supplier: OM10100
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• On-chip Dac: 1-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 622-1025 - KIT DEV IND REF DESIGN LPC2468622-1024 - BOARD SCKT ADAPTER FOR TFBGA208568-4358 - DISPLAY QVGA TFT FOR OM10100568-4309 - BOARD EXTENSION LPCSTICK568-4308 - EVAL LPC-STICK WITH LPC2468MCB2400U - BOARD EVAL MCB2400 + ULINK2MCB2400 - BOARD EVAL FOR NXP LPC246X SER622-1005 - USB IN-CIRCUIT PROG ARM7 LPC2K
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 568-4261; 935282457551; LPC2468FBD208-S

NXP Semiconductors
UM10237_4
User manual
Fig 32. Transmit Flow Control
MirrorCounter
device driver
(1/515 bit
slots)
transmit
register
receive
(R)MII
(R)MII
writes
0
MirrorCounter
PauseTimer
TxFlowCtl
transmission
9.12 Half-Duplex mode backpressure
normal
50
Transmit flow control is enabled via the ‘TX FLOW CONTROL’ bit in the MAC1
configuration register. If the ‘TX FLOW CONTROL’ bit is zero, then the MAC will not
transmit pause control frames, software must not initiate pause frame transmissions, and
the TxFlowControl bit in the Command register should be zero.
Transmit flow control example
Figure 11–32
In this example, a frame is received while transmitting another frame (full duplex.) The
device driver detects that some buffer might overrun and enables the transmit flow control
by programming the PauseTimer and MirrorCounter fields of the FlowControlCounter
register, after which it enables the transmit flow control by setting the TxFlowControl bit in
the Command register.
As a response to the enabling of the flow control a pause control frame will be sent after
the currently transmitting frame has been transmitted. When the pause frame
transmission completes the internal mirror counter will start counting bit slots; as soon as
the counter reaches the value in the MirrorCounter field another pause frame is
transmitted. While counting the transmit datapath will continue normal transmissions.
As soon as software disables transmit flow control a zero pause control frame is
transmitted to resume the receive process.
When in half-duplex mode, backpressure can be generated to stall receive packets by
sending continuous preamble that basically jams any other transmissions on the Ethernet
medium. When the Ethernet block operates in half duplex mode, asserting
the TxFlowControl bit in the Command register will result in applying continuous preamble
on the Ethernet wire, effectively blocking traffic from any other Ethernet station on the
same segment.
normal receive
pause control
transmission
frame
100
illustrates the transmit flow control.
150
normal transimisson
Rev. 04 — 26 August 2009
200
250
pause in effect
pause control
transmission
frame
300
TxFlowCtl
clear
350
Chapter 11: LPC24XX Ethernet
pause control
transmission
frame
400
UM10237
© NXP B.V. 2009. All rights reserved.
normal receive
450
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500