自制USB接口ISP下载线

本站 WWW.RunMCU.COM 语：USB接口的AVRISP线对AVR开发人员来说，是一个非常好的选择，它不仅仅可以为节省USB—>串口线（便携机），另一个方便就是你稍稍加以改造就可以使用上一个“”电源（USB电源）

资料://www.matwei.de/eng/index.php?page1=elektronik&page2=usbisp
The USBisp is another AVR programmer. Compared to the other freely available programmers out there mine has some advantages, I think:
USB-Interface
The USBisp is very interesting on notebooks where no serial or parallel port is available
STK500-Protocol
The USBisp is compatible to AVR Studio but also to much other programs supporting this protocol. For Example, these programs are avrdude and uisp.
fast
The USBisp is due to the fast USB interface but also due to the high SPI clock very fast compared to the original AVRisp from Atmel or the simple parallel dongles. The isp clock frequency is adjustable from 2MHz down to about 60kHz via the STK500 protocol. More, even slower, frequencies are planned to be implemented so that AVR with slower clock rates can be programmed.
updates are easy
The firmware of the USBisp is easy to upgrade. A software upgrade works also via the USB interface. The package contains a STK500 compatible bootloader so you can use avrdude to update the firmware. There are 7k of flash left in the ATMega8
open
The USBisp is not only a AVR programmer. Due to the open schematic and the bootloader you can use the hardware also as a general USB platform. With a simple port expander (some shift registers) you can develop your own USB light show or a USBlcd.
The hardware:
There are two important chips on the USBisp. One is the FT245BM which connects the other important chip, an ATMega8, to the USB. Due to the parellel interface between the FT245BM and the ATMega8 the data throughput between them and the PC can reach easily 6MBit. The PC driver creates a virtual COM port (COMx respectively /dev/ttyUSBx) so that no special software is needed to talk to the USBisp. The ATMega8 is responsible for the conversion between the STK500 protocol and the SPI data channel to the target AVR. Additionally there is a EEPROM connected to the FT245BM which contains some configuration for that chip. Also there is a 4MBit dataflash in the schematic but this is not necessary for the USBisp. It's a hangover from another project with the same hardware. The PCB (I will not release the CAD data of it) has the same outline than that of the original AVRISP from Atmel. So you can easily update your current AVRisp to USB.
The software:
Application and bootloader are written in C. The bootloader is a minimized of the application so that it fits into 1024 byte.

以下为 fsclub 网友的翻译

翻译参考(欢迎交流指正:)
USBISP是另外一个种编程器,和其它的自由()编程器相比,我这个编程器有一些优点,我认为:
USB接口
这个USBISP支持STK-500协议,在一些没有串口或者并口的笔记本上是很有用的,
USBISP兼容AVR STUDIO,其实很多编程器也支持这个协议,像avrdude 和 uisp
快速
USBISP由于快速的USB接口和高速的SPI总线,与原来的AVRISP或者简单的并口线相比,其速度是很快的.这个器通过STK500协议,具有2M到60KHZ可调的频率.更多地,计划支持甚至更慢的频率,因此低频率的AVR芯片也可以被编程.
升级更容易
固件很容易升级,软件的升级是通过USB接口来完成的,这软件包中包含兼容STK500的BOOTLOAD,你可以通过avrdude来升级固件.在M8中可以用的程序空间为7K.
开放
这个USBISP不只是一个AVR编程器,因为开放的电路和BOOTLOAD,你可以用这个硬件来作为一个通用的USB接口平台, 通过一些端口的简单扩展(一些移位寄存器),你可以自己开发你自己的USBLIGHT SHOW或者USB LCD.
硬件
在这里用了两个重要的芯片.一个是FT245BM,它连接另一个重要的芯片MEGA8,另一边连着USB接口.因为FT245BM与M8之间通过并行口联接,所以在PC和M8之间可以很容易的就达到6MBIT的速度.PC上的驱动程序会生成一个虚拟的COM口,所以在电脑上不需要特殊的上位机软件与USBISP相联.MEGA8负责以STK500协议传输与SPI数据与目标AVR单片机.,另外增加一个EEPROM来保存一些FT245BM的配置数据.在电路图中的4MB的FLASH对USBISP来说不是必须的. 这是另一个与这个硬件电路相同的项目中残留下来的.电路板(我不会发布相关的CAD电子文件)与AVRISP具有大体相同的轮廓,你可以很简单的把你的连接USB的AVRISP电路升级到USBISP.
软件:
程序和BOOTLOAD都是用C写的,BOOTLOAD已经化,所以可以适合1024B的BOOTLOAD
这里为外文网站地址:
usbisp_05_10_04.tar.bz2
usbisp_05_10_04.zip
usbisp_21_04_05.tar.bz2
usbisp_21_04_05.zip

以下介绍，是关于此线，引自 OURAVR

使用真正USB芯片及M8的ISP

这是用M8制作真正USB接口ISP编程，上位机用AVRstudioSTK500软件。 AVR代码为C。不是软件模拟的USB。

实物图：

原理图：

零件装配图：

完整的制作资料、C源代码、烧录文件：USBISP