What the hell is an ATMEL AVR?

Atmel's AVR microcontrollers have a RISC core running single cycle instructions and a well- defined I/O structure that limits the need for external components. Internal oscillators, timers, UART, SPI, pull-up resistors, pulse width modulation, ADC, analog comparator and watch dog timers are some of the features you will find in AVR devices.

AVR instructions are tuned to decrease the size of the program whether the code is written in C or Assembly. With on-chip in-system programmable Flash and EEPROM, the AVR is a perfect choice in order to optimize cost and get product to the market quickly.

The chips allow the program memory to be reprogrammed in-system through a SPI serial interface. This provides a highly flexible and cost effective solution to many embedded control applications.

What the hell is an AT89S8252?

The AT89S8252 is a 80C51 compatible 8-bit single chip microcontroller with 8k internal code and
2k data flash on chip. The chip allows the program memory to be reprogrammed in-system
through a SPI serial interface. This provides a highly flexible and cost effective
solution to many embedded control applications.

The chip has the following features:
- 80C51-compatible core (you'll find a lot of tools for this device)
- in-system programmable by this tool
- 8k protectable downloadable flash
- 2k EEPROM
- 256 Bytes RAM
- 32 I/O lines
- three 16 bit timer/counters
- a six-level interrupt architecture with nine interrupt sources
- a full duplex serial interface
- pretty cheap (less than $10 I guess)
- ... and many more ...

How to build the programming interface

All you need to program the device is this program and five wires from
your PC to the target board. There is no additional hardware (like a programmer) required.

Your code needs to be in raw BIN format.
(if your compiler generates HEX-Files, use a "HEX to BIN" converter. I added a HEX2BIN which I found in the internet for free)

ISP - programming cable

Connect PC and chip as follows:

Printer Port	ATMEL
Pin:6 (D4)	RESET
Pin:7 (D5)	MOSI
Pin:8 (D6)	SCK
Pin:10 (ACK)	MISO
Pin:20 (GND)	GND

The cable should not be longer than 2m to avoid electrical reflections.

Don't forget to:

ATMEL AVR

• connect a xtal and two capacitors (22pF) (See datasheed)
  
  
• use 5V power supply
  
  
• connect a resistor from RESET to VCC
  
  
• connect an capacitor (100nF) between Vcc and Ground as close to the chip as possible --> avoid long lines
  
  
• avoid differences in ground potential between your target hardware and the PC
  
  
• check what is connected to the portpins MOSI, MISO and SCK. These pins are used to program the
  chip. Your target board could response to these signals if something is connected to these pins.
  

AT89S8252

• strap /EA (Pin 31 uC) to Vcc to operate from internal flash-memory
  
  
• connect a xtal (4 - 24MHz) and two capacitors (22pF) (See datasheed)
  
  
• use 5V power supply
  
  
• connect a capacitor and a resistor to RESET to get a power on reset
  
  
• connect pullups to P0 if this port is used as output
  
  
• connect an capacitor (100nF) between Vcc and Ground as close to the chip as possible --> avoid long lines
  
  
• avoid differences in ground potential between your target hardware and the PC
  
  
• check what is connected to the portpins P1.5, P1.6 and P1.7. These pins are used to program the
  chip. Your target board could response to these signals if something is connected to these pins.

Test mode

In case of problems

ATMEL AVR

How to use the software:

Download the program and extract the ZIP-file.

Connect the micrcontroller to your PC and start the program with the following parameters:

Usage: ISP_AVR.EXE /LPTn [/ERASE] [/LOCK] [/SLOW] [/READ] [/DATA] [/BO] [/TEST] <file>

description:

• /LPTn use LPT1, LPT2 or LPT3 to select the printer port
• /ERASE Erase code and data memory before writing
  
• /LOCK Set lock bits after writing
  
• /SLOW Use slower data transfer (in case of problems)
  
• /READ Read code/data memory
  
• /DATA Program/Read the 2k data memory instead of code memory
  
• /TEST Start hardware test mode
• /BO programs the brown-out fuses (if avalible). (4V and Reset 256ms +16k * ck) (see data sheed)
  
  
  Example 1:
  Write the file PROGRAM.BIN into the CODE memory and erase the chip first.
  The Programmer is connected to LPT1.
  ISP_AVR.EXE /LPT1 /ERASE PROGRAM.BIN
  
  Example 2:
  Write the file DAT1.BIN into the DATA memory and do not erase the chip.
  The Programmer is connected to LPT1.
  ISP_AVR.EXE /LPT1 /DATA DAT1.BIN
  
  Example 3:
  Read the DATA memory and write to file CODE.BIN
  The Programmer is connected to LPT2.
  ISP_AVR.EXE /LPT2 /READ CODE.BIN
  
  Example 4:
  Read the DATA memory and write to file DAT2.BIN
  The Programmer is connected to LPT2.
  ISP_AVR.EXE /LPT2 /READ /DATA DAT2.BIN
  

AT89S8252

How to use the software:

Download the program and extract the ZIP-file.

Connect the micrcontroller to your PC and start the program with the following parameters:

Usage: ISP_HB.EXE /LPTn [/ERASE] [/LOCK] [/SLOW] [/READ] [/DATA] [/TEST] <file>


description:

• /LPTn use LPT1, LPT2 or LPT3 to select the printer port
• /ERASE Erase code and data memory before writing
  
• /LOCK Set lock bits after writing
  
• /SLOW Use slower data transfer (in case of problems)
  
• /READ Read code/data memory
  
• /DATA Program/Read the 2k data memory instead of code memory
• /TEST Start hardware test mode
  
  
  
  
  Example 1:
  Write the file PROGRAM.BIN into the CODE memory and erase the chip first.
  The Programmer is connected to LPT1.
  ISP_HB.EXE /LPT1 /ERASE PROGRAM.BIN
  
  Example 2:
  Write the file DAT1.BIN into the DATA memory and do not erase the chip.
  The Programmer is connected to LPT1.
  ISP_HB.EXE /LPT1 /DATA DAT1.BIN
  
  Example 3:
  Read the DATA memory and write to file CODE.BIN
  The Programmer is connected to LPT2.
  ISP_HB.EXE /LPT2 /READ CODE.BIN
  
  Example 4:
  Read the DATA memory and write to file DAT2.BIN
  The Programmer is connected to LPT2.
  ISP_HB.EXE /LPT2 /READ /DATA DAT2.BIN