First, thank you for your previous post, it is the circuit diagram that provides circuit, which is the circuit diagram with protective diodes.
Just a few days ago, I also saw a circuit diagram and related information on the Internet. The circuit is the basic difference between the circuit, the main difference between 232 converted.
My circuit diagram made a simplified improvement on the basis of the early circuit diagram, removed 244, now only MEGA16 and low voltage RS232 conversion chip SIPEX3223EEY, support 2.7V-5.5V supply voltage, power supply is provided by the target board, there is power and ACT Indicates that the cost is about 50 yuan.
1. First use the PonyProg's ISP function, write the boot code, so that you can use Studio's upgrade function. After writing, you will write the fuse bit (mainly programming bootrst), so that the chip is started to enter the boot code. segment.
2. Then start AVR Studio4.06 (I am using this version), enter avrog, transfer to Upgrade.edn, execute Program, will appear and prompt is writing and programming, if the prompt does not find the target board, most of the last half It is no programming in your bootrst bit, maybe you need to re-run AVR Studio. After completing, go back to PonyProg, restore Bootrst to the unsuclated state.
3. After running, the ACT lamp is always on, it may indicate that it is looking for a connection, plug in a serial line. The target board must first program the JTAGEN and OCDEN of the chip so that JTAG debugging can be used.
4. After connecting, run AVR Studio, select Debug-> Select Platform and Device, select JTAG ICE, choose the chip model to simulate, it is OK. After the connection is normally, under the Debug menu, the JTAG ICE Option option is available.
5. Have a small LED scintillation program, run normal!
Production information link:
Http://www.21icsearch.com/buzi/upimage/upfile/20031020946440.jpg,
After downloading, change the extension to rar, including the schematic, PCB diagram, ROM file, fuse setting, etc., I wish you all a smooth!
At present, the high-end models of the AVR microcontroller basically support JTAG debugging. The specific signal can be refer to the list of JTAGICE support chips on the Atmel website. When you design: JTAG's 4 lines will not be used as ordinary after use as debug interface. The IO port is used, which is described in the manual.
I took a few words about the working principle of this board. MEGA16 on the ICE board is a monitoring chip, an internal operation monitor, not a Boot program (the use of the boot program is written to the user program), so bootrst is canceled. Some friends said that the resistance would omitted what the chip would be locked. In fact, as long as the reset circuit on the board is improved, let his reset time can be longer. 430 single-chip reset is generally good, there are some jitter when the power is turned on, it will cause a crash. In contrast, AVR is much better, my board is usually a 10K pull and a 0.1uf capacitor, I haven't met it. The case where the reset is abnormal.
The INT0 of the target board is reset into the monitoring chip is useful, and you can increase it by yourself.
If you need a finished product, I can help everyone do some, just see how much people, please contact
. EN1jun913@21cn.com.
