参数资料
型号: M68LC302CAF16VCT
厂商: FREESCALE SEMICONDUCTOR INC
元件分类: 微控制器/微处理器
英文描述: 4 CHANNEL(S), 10M bps, LOCAL AREA NETWORK CONTROLLER, PQFP100
封装: 14 X 14 MM, 1.40 MM HEIGHT, 0.50 MM PITCH, PLASITC, LQFP-100
文件页数: 82/128页
文件大小: 641K
代理商: M68LC302CAF16VCT
ETHERNET Controller
4-18
MC68EN302 REFERENCE MANUAL
MOTOROLA
CSL—Carrier Sense Lost, written by Ethernet controller (only valid if L = 1).
Carrier sense dropped out or was never asserted during a collision free frame transmission.
Data Length, written by user.
Data length is the number of octets the Ethernet controller should transmit from this BD’s
data buffer. It is never modified by the Ethernet controller. The value of this field must be
greater than zero.
Tx Buffer Pointer, written by user.
The transmit buffer pointer containing the address of the associated data buffer, may be
even or odd. The buffer must reside in memory external to the MC68EN302. This value is
never modified by the Ethernet controller.
4.3 DMA AND BUFFER DESCRIPTOR LOGIC
The DMA and buffer descriptor modules transfer data between external memory and the TX/
RX FIFOs.
4.3.1 BUFFER DESCRIPTOR LOGIC
Buffer descriptors are stored in the on-chip dual-port RAM. The RAM is sufficient to store
128 buffer descriptors of 4 sixteen-bit-words. The features of the BD circuitry are as follows:
Flexible Buffer Descriptor allocation between transmit and receive;
Multiple buffers per frame
Transmit buffers may start on any byte boundary, Receive buffers must start on even
byte boundaries.
Maximum Receive Buffer size is user controllable;
The Buffer Descriptor space is divided between transmit and receive in various
configurations depending on the value of BDSIZE in the EDMA register. Table 4-2 shows
the starting and ending addresses (offset from MOBA) in the BD RAM for the four options.
The Maximum Receive Buffer Length field (MRBL) in the EMRBLR register determines the
default length of all receive buffers besides the last buffer of a frame (the last buffer is usually
shorter in length than the preceding buffers).
On the transmit side, the MC68EN302 may have up to two separate frames with open
buffers at a specific point in time. While the first frame completes the transmit process, DMA
Table 4-2. BD RAM Address Ranges
BDSIZE
TRANSMIT BUFFER
DESCRIPTOR RANGE
RECEIVE BUFFER
DESCRIPTOR RANGE
NUMBER OF TRANSMIT
BUFFERS
NUMBER OF RECEIVE
BUFFERS
$00
$C00 - $C3F
$C40 - $FFF
8
120
$01
$C00 - $C7F
$C80 - $FFF
16
112
$10
$C00 - $CFF
$D00 - $FFF
32
96
$11
$C00 - $DFF
$E00 - $FFF
64
相关PDF资料
PDF描述
MC68CK16Z1CAG16 16-BIT, 16.78 MHz, MICROCONTROLLER, PQFP144
MC908GR48AVFUR2 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQFP64
MC908GZ60CFAE 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQFP48
MC908GZ60VFJE 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQFP32
MC9S08RE32FGE 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQFP44
相关代理商/技术参数
参数描述
M68LC302CAF20VCT 功能描述:微处理器 - MPU 68K INTGR COM PROC DMA 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
M68LC302CPU16VCT 功能描述:IC MPU NETWORK 16MHZ 100-LQFP RoHS:否 类别:集成电路 (IC) >> 嵌入式 - 微处理器 系列:M683xx 标准包装:2 系列:MPC8xx 处理器类型:32-位 MPC8xx PowerQUICC 特点:- 速度:133MHz 电压:3.3V 安装类型:表面贴装 封装/外壳:357-BBGA 供应商设备封装:357-PBGA(25x25) 包装:托盘
M68LC302CPU20VCT 功能描述:IC MPU NETWORK 20MHZ 100-LQFP RoHS:否 类别:集成电路 (IC) >> 嵌入式 - 微处理器 系列:M683xx 标准包装:2 系列:MPC8xx 处理器类型:32-位 MPC8xx PowerQUICC 特点:- 速度:133MHz 电压:3.3V 安装类型:表面贴装 封装/外壳:357-BBGA 供应商设备封装:357-PBGA(25x25) 包装:托盘
M68LGL061X 制造商:Panasonic Industrial Company 功能描述:SUB ONLY CRT
M68LGL061XA 制造商:Panasonic Industrial Company 功能描述:CRT OR M68LGL061X