LPC2468FET208,551 NXP Semiconductors, LPC2468FET208,551 Datasheet - Page 257

• Manufacturer Part Number: LPC2468FET208,551
• Description: IC ARM7 MCU FLASH 512K 208TFBGA
• Manufacturer: NXP Semiconductors
• Series: LPC2400r

Specifications of LPC2468FET208,551

• Program Memory Type: FLASH
• Program Memory Size: 512KB (512K x 8)
• Package / Case: 208-TFBGA
• 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
• Package: 208TFBGA
• Device Core: ARM7TDMI-S
• Family Name: LPC2000
• Maximum Speed: 72 MHz
• 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: 568-4262; 935283234551; LPC2468FET208-S

NXP Semiconductors
UM10237_4
User manual
(0x7FE0 11F8) to the TxStatus register. The device driver writes the number of descriptors
and statuses minus 1(3) to the TxDescriptorNumber register. The descriptors and
statuses in the arrays need not be initialized, yet.
At this point, the transmit datapath may be enabled by setting the TxEnable bit in the
Command register. If the transmit datapath is enabled while there are no further frames to
send the TxFinishedInt interrupt flag will be set. To reduce the processor interrupt load
only the desired interrupts can be enabled by setting the relevant bits in the IntEnable
register.
Now suppose application software wants to transmit a frame of 12 bytes using a TCP/IP
protocol (in real applications frames will be larger than 12 bytes). The TCP/IP stack will
add a header to the frame. The frame header need not be immediately in front of the
payload data in memory. The device driver can program the Tx DMA to collect header and
payload data. To do so, the device driver will program the first descriptor to point at the
frame header; the Last flag in the descriptor will be set to false/0 to indicate a
multi-fragment transmission. The device driver will program the next descriptor to point at
the actual payload data. The maximum size of a payload buffer is 2 kB so a single
descriptor suffices to describe the payload buffer. For the sake of the example though the
payload is distributed across two descriptors. After the first descriptor in the array
describing the header, the second descriptor in the array describes the initial 8 bytes of
the payload; the third descriptor in the array describes the remaining 4 bytes of the frame.
In the third descriptor the Last bit in the Control word is set to true/1 to indicate it is the last
descriptor in the frame. In this example the Interrupt bit in the descriptor Control field is set
in the last fragment of the frame in order to trigger an interrupt after the transmission
completed. The Size field in the descriptor’s Control word is set to the number of bytes in
the fragment buffer, -1 encoded.
Note that in real device drivers, the payload will typically only be split across multiple
descriptors if it is more than 2 kB. Also note that transmission payload data is forwarded to
the hardware without the device driver copying it (zero copy device driver).
After setting up the descriptors for the transaction the device driver increments the
TxProduceIndex register by 3 since three descriptors have been programmed. If the
transmit datapath was not enabled during initialization the device driver needs to enable
the datapath now.
If the transmit datapath is enabled the Ethernet block will start transmitting the frame as
soon as it detects the TxProduceIndex is not equal to TxConsumeIndex - both were zero
after reset. The Tx DMA will start reading the descriptors from memory. The memory
system will return the descriptors and the Ethernet block will accept them one by one
while reading the transmit data fragments.
As soon as transmission read data is returned from memory, the Ethernet block will try to
start transmission on the Ethernet connection via the (R)MII interface.
After transmitting each fragment of the frame the Tx DMA will write the status of the
fragment’s transmission. Statuses for all but the last fragment in the frame will be written
as soon as the data in the frame has been accepted by the Tx DMA manager. The status
for the last fragment in the frame will only be written after the transmission has completed
on the Ethernet connection.
Rev. 04 — 26 August 2009
Chapter 11: LPC24XX Ethernet
UM10237
© NXP B.V. 2009. All rights reserved.
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