Summary of Experimenting the AT90S8535 with Code Vision AVR C Compiler
This article introduces In-System Programming (ISP) for AVR chips using CodeVisionAVR, highlighting its simplicity and low cost. It details the construction of a custom ISP cable utilizing a 74LS245 tristate buffer to manage data flow during programming via serial or parallel ports. The text also outlines the basic hardware requirements for experimenting with the AT90S8535 microcontroller, including a voltage regulator and an 8MHz crystal oscillator.
Parts used in the Build an ISP Cable:
- 74LS245 octal tristate buffer
- Small LED (optional)
- 10k resistor
- AT90S8535 microcontroller
- +5V regulator IC
- 8MHz X-tal
- Resistors
- Capacitors
Introduction
The ISP (In System Programmable) of the AVR chips provides a very simpleand very cheap for hobbyist to learn and build application with AVR chips.I have got the evaluation version of CodeVisionAVR,from my friend. The CodeVision is an IDE for AVR chips having built-insoftware for STK200 compatible programmer. After compiling the source programin C, the Intel-HEX file or ATMEL-ROM file can be downloaded into the chipdirectly. The ISP has only four signal to implement, i.e., MOSI, MISO,SCK, RESET. Many free programmers connecting through PC’s serial or parallelport are available. Mostly the programmer’s designer developed their ownISP software for DOS, Window, or Linux platform. The popular one is PonyProgby Claudio Lanconelli. The PonyProg is capable of writingthe HEX code into the chip with many serial protocol. Many downloader circuitscan also easily be used with PonyProg. The evaluation board for AVR chipfrom ATMEL, STK200 is the most referable by many tool developers.As mentioned earlier, the CodeVision also provides the programmer softwarefor STK200 compatible. I have adapted a simple ISP cable with a tristatebuffer and used it with the CodeVision, it’s so cool. The simple ISP cableworks very nice with CodeVision.
Build an ISP Cable
Figure 1 shows a circuit diagram of ISP cable. The 74LS245, an octaltristate buffer provides the float state after the hex code has been writteninto the chip. Small LED is optional. The 10k resistor pulling pin19 upto +5V will disable all outputs to float state when disconnects LPT1.
The AT90S8535 Circuit
To do simple experiment, you need only a single chip microcontrollerAT90S8535, a regulator IC for +5V supply and an 8MHz X-tal. The otherspassive components are small resistor, and capacitor.
For more detail: Experimenting the AT90S8535 with Code Vision AVR C Compiler
- What is the primary benefit of ISP for hobbyists?
It provides a very simple and very cheap method to learn and build applications with AVR chips. - How many signals are required to implement ISP?
ISP requires only four signals: MOSI, MISO, SCK, and RESET. - Which software is popular for writing HEX code via serial protocols?
PonyProg by Claudio Lanconelli is a popular tool capable of writing HEX code into the chip. - What component allows outputs to float when disconnecting LPT1?
A 10k resistor pulling pin 19 up to +5V disables all outputs to a float state. - Can CodeVisionAVR be used with STK200 compatible programmers?
Yes, CodeVisionAVR has built-in software specifically for STK200 compatible programmers. - What passive components are needed for the AT90S8535 circuit?
The circuit requires small resistors and capacitors along with a regulator IC and an 8MHz X-tal. - Does the ISP cable design include an optional indicator?
Yes, a small LED is included as an optional part of the ISP cable circuit.
