LPC2468FBD208,551 NXP Semiconductors, LPC2468FBD208,551 Datasheet - Page 253

• 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
When there is a multi-fragment transmission for fragments other than the last, the Last bit
in the descriptor must be set to 0; for the last fragment the Last bit must be set to 1. To
trigger an interrupt when the frame has been transmitted and transmission status has
been committed to memory, set the Interrupt bit in the descriptor Control field to 1. To have
the hardware add a CRC in the frame sequence control field of this Ethernet frame, set
the CRC bit in the descriptor. This should be done if the CRC has not already been added
by software. To enable automatic padding of small frames to the minimum required frame
size, set the Pad bit in the Control field of the descriptor to 1. In typical applications bits
CRC and Pad are both set to 1.
The device driver can set up interrupts using the IntEnable register to wait for a signal of
completion from the hardware or can periodically inspect (poll) the progress of
transmission. It can also add new frames at the end of the descriptor array, while
hardware consumes descriptors at the start of the array.
The device driver can stop the transmit process by resetting the TxEnable bit in the
Command register to 0. The transmission will not stop immediately; frames already being
transmitted will be transmitted completely and the status will be committed to memory
before deactivating the datapath. The status of the transmit datapath can be monitored by
the device driver reading the TxStatus bit in the Status register.
As soon as the transmit datapath is enabled and the corresponding TxConsumeIndex and
TxProduceIndex are not equal i.e. the hardware still needs to process frames from the
descriptor array, the TxStatus bit in the Status register will return to 1 (active).
Tx DMA manager reads the Tx descriptor array
When the TxEnable bit is set, the Tx DMA manager reads the descriptors from memory at
the address determined by TxDescriptor and TxConsumeIndex. The number of
descriptors requested is determined by the total number of descriptors owned by the
hardware: TxProduceIndex - TxConsumeIndex. Block transferring descriptors minimizes
memory loading. Read data returned from memory is buffered and consumed as needed.
Tx DMA manager transmits data
After reading the descriptor the transmit DMA engine reads the associated frame data
from memory and transmits the frame. After transfer completion, the Tx DMA manager
writes status information back to the StatusInfo and StatusHashCRC words of the status
field. The value of the TxConsumeIndex is only updated after status information has been
committed to memory, which is checked by an internal tag protocol in the memory
interface. The Tx DMA manager continues to transmit frames until the descriptor array is
empty. If the transmit descriptor array is empty the TxStatus bit in the Status register will
return to 0 (inactive). If the descriptor array is empty the Ethernet hardware will set the
TxFinishedInt bit of the IntStatus register. The transmit datapath will still be enabled.
The Tx DMA manager inspects the Last bit of the descriptor Control field when loading the
descriptor. If the Last bit is 0, this indicates that the frame consists of multiple fragments.
The Tx DMA manager gathers all the fragments from the host memory, visiting a string of
frame descriptors, and sends them out as one Ethernet frame on the Ethernet connection.
When the Tx DMA manager finds a descriptor with the Last bit in the Control field set to 1,
this indicates the last fragment of the frame and thus the end of the frame is found.
Update ConsumeIndex
Rev. 04 — 26 August 2009
Chapter 11: LPC24XX Ethernet
UM10237
© NXP B.V. 2009. All rights reserved.
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