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E2PROM Memory
As can be seen in Figure 5-6, the FLASH CS is distributed to four CS signals. The
distribution depends on the size of the FLASH module installed - it is read by the BCSR
using the PD(1-7) pins.
The Hard-Reset configuration word stored in the FLASH differs from the one stored in the
E 2 PROM in the BPS field which is the Boot Port Size - the E 2 PROM is 8 bits while the
FLASH is 32 bits.
5.7.1
Flash Programming Voltage
Support is given to 5V- and 12-V programmable modules. The selection between V PP
voltage levels is done with a dedicated jumper. To avoid inadvertent programming or
erasure of the Flash, Motorola recommends leaving the jumper open so that no V PP is
applied to the Flash SIMM.
5.8
E 2 PROM Memory
The MPC8272ADS is provided with 8KBytes of E 2 PROM memory in a PLCC package.
The E 2 PROM resides on a socket in case it is desired to replace or re-program a different
configuration for the board. The E 2 PROM is used only for the purpose of supplying the
Reset Configuration Word during power-on reset and for storing the PCI configuration
data. It is used as a back-up for the Flash memory in case the Flash is not installed or the
data it holds is incorrect. As a back-up, it holds the default Hard-Reset configuration word
and the default PCI configuration. The Hard-Reset configuration word stored in the
E 2 PROM differs from the one stored in the FLASH in the BPS field which is the Boot Port
Size - the E 2 PROM is 8 bits while the FLASH is 32 bits. It uses a single chip-select, CS0
or CS4, which depends on the chip-select used by the Flash. The selection of the chip-select
is done by a dip-switch. The E 2 PROM connection scheme is shown in Figure 5-7.
The device used is ATMEL AT28HC64B, a 5-V Byte alterable E 2 PROM, 150ns access
time with byte-wide JEDEC pinout. Although the device is placed in a socket, it can be
programmed onboard. In order to program the device onboard, it must be unlocked - it can
be locked to prevent unauthorized alterations of its contents. The lock can be done by
hardware or software. The hardware lock is done by write inhibit - the MPC8272 does not
assert WE during write cycles (set in the BRx register). The software lock is achieved by
writing a unique sequence to the device. To unlock, a different unique sequence has to be
written
Chapter 5. Module Design
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相关代理商/技术参数
MPC8272CVR 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:MPC8272 PowerQUICC II Family Hardware Specifications
MPC8272CVRB 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:PowerQUICC II⑩ Family Hardware Specifications
MPC8272CVRE 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:PowerQUICC II⑩ Family Hardware Specifications
MPC8272CVRI 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:PowerQUICC II⑩ Family Hardware Specifications
MPC8272CVRM 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:PowerQUICC II⑩ Family Hardware Specifications
MPC8272CVRMIBA 功能描述:微处理器 - MPU 266 MHz 505.4 MIPS RoHS:否 制造商:Atmel 处理器系列:SAMA5D31 核心:ARM Cortex A5 数据总线宽度:32 bit 最大时钟频率:536 MHz 程序存储器大小:32 KB 数据 RAM 大小:128 KB 接口类型:CAN, Ethernet, LIN, SPI,TWI, UART, USB 工作电源电压:1.8 V to 3.3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:FBGA-324
MPC8272CVRP 制造商:FREESCALE 制造商全称:Freescale Semiconductor, Inc 功能描述:PowerQUICC II⑩ Family Hardware Specifications
MPC8272CVRPIEA 功能描述:微处理器 - MPU 300 MHz 570 MIPS RoHS:否 制造商:Atmel 处理器系列:SAMA5D31 核心:ARM Cortex A5 数据总线宽度:32 bit 最大时钟频率:536 MHz 程序存储器大小:32 KB 数据 RAM 大小:128 KB 接口类型:CAN, Ethernet, LIN, SPI,TWI, UART, USB 工作电源电压:1.8 V to 3.3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:FBGA-324