Krunal_299 wrote: Basically factory settled AT89C51ED2 can be programmed via HVPP or USART. Pdf Editor Without Watermark there. But by using modified Bootloader (at user end), it is possible to program the built-in Flash of the controller via SPI terminals. Is this perception of mine is Right? Yes, if you first load your Modified Bootloader, via either HVPP or USART. You can then use the BLJB to go to your loader. There is of course the AT89LP51ED2, which is largely equivalent, is faster, and includes SPI programming, as well as USART ROM loader.

(& it is usually cheaper too.) That will be much easier than coding a SPI slave in SW. David.prentice wrote: Although the Atmel and NXP devices hold their bootloader in a protected area, I believe that you can replace them, but I don't know the procedure. Why do you want SPI when the UART works fine? Most Atmel BOOT loaders are in ROM, but they do have a second area for User Loaders, which can patch-in via the BLJB fuse.

1 Applies to shipping within Ukraine. Information about shipping policies for other countries can be found here: Payment and Delivery Information 2 In accordance with.

In some AT89 parts, the SPI gives slightly more easy fuse access than the UART loader. To have full control over BOOT start, you need to access RXD/TXD and also RST and PSEN, it may be the OP simply has better SPI access. (I'd still suggest a swap to the newer LP51ED2, as the SPI is simply there: all done, in HW, and waiting.). If you have an RS232 socket on the board, you can use the regular bootloader.

Likewise with an on-board FTDI TTL->USB chip. You just use the FLIP software. It just seems a lot of f*rting about to write a custom SPI bootloader.

Then asking wek or danni how to install the new bootloader. Bear in mind that your customers will be stuck with your non-standard bootloader and your non-standard software. If you stick with the standard, the whole world can use FLIP (whatever its faults). I have only used the NXP P89C51RD2. This is very similar to the Atmel AT89C51RD2. The ED2 has extra 'features'. Mind you, the average AVR is a lot better endowed (and convenient).