LPC2468FET208,551 NXP Semiconductors, LPC2468FET208,551 Datasheet - Page 101

• 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

1. How to read this chapter
2. Introduction
3. Operation
UM10237_4
User manual
The Memory Accelerator Module operates in combination with the flash controller and is
available in parts LPC2458/68/78.
The MAM block in the LPC2400 maximizes the performance of the ARM processor when
it is running code in Flash memory using a single Flash bank.
Simply put, the Memory Accelerator Module (MAM) attempts to have the next ARM
instruction that will be needed in its latches in time to prevent CPU fetch stalls. The
LPC2400 uses one bank of Flash memory, compared to the two banks used on
predecessor devices. It includes three 128 bit buffers called the Prefetch buffer, the
Branch Trail Buffer and the data buffer. When an Instruction Fetch is not satisfied by either
the Prefetch or Branch Trail buffer, nor has a prefetch been initiated for that line, the ARM
is stalled while a fetch is initiated for the 128 bit line. If a prefetch has been initiated but not
yet completed, the ARM is stalled for a shorter time. Unless aborted by a data access, a
prefetch is initiated as soon as the Flash has completed the previous access. The
prefetched line is latched by the Flash module, but the MAM does not capture the line in
its prefetch buffer until the ARM core presents the address from which the prefetch has
been made. If the core presents a different address from the one from which the prefetch
has been made, the prefetched line is discarded.
The prefetch and Branch Trail buffers each include four 32 bit ARM instructions or eight
16 bit Thumb instructions. During sequential code execution, typically the prefetch buffer
contains the current instruction and the entire Flash line that contains it.
The MAM uses the LPROT[0] line to differentiate between instruction and data accesses.
Code and data accesses use separate 128 bit buffers. 3 of every 4 sequential 32 bit code
or data accesses "hit" in the buffer without requiring a Flash access (7 of 8 sequential
16 bit accesses, 15 of every 16 sequential byte accesses). The fourth (eighth, 16th)
sequential data access must access Flash, aborting any prefetch in progress. When a
Flash data access is concluded, any prefetch that had been in progress is re-initiated.
Timing of Flash read operations is programmable and is described later in this section.
In this manner, there is no code fetch penalty for sequential instruction execution when the
CPU clock period is greater than or equal to one fourth of the Flash access time. The
average amount of time spent doing program branches is relatively small (less than 25%)
and may be minimized in ARM (rather than Thumb) code through the use of the
conditional execution feature present in all ARM instructions. This conditional execution
may often be used to avoid small forward branches that would otherwise be necessary.
UM10237
Chapter 6: LPC24XX Memory Accelerator Module (MAM)
Rev. 04 — 26 August 2009
Rev. 04 — 26 August 2009
© NXP B.V. 2009. All rights reserved.
User manual
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