Need parallel programmer for AT89C51RD2

[EduardoLM]

Please, what is the simplest parallel programmer that works with AT89C51RD2? I have a Willem 3.1, but it seems the latest software version (0.97ja) doesn't support this part.

Normally, the AT89C51RD2 can be programmed by RS232 ISP using the built-in bootloader, but I have some chips with the bootloader damaged, so I must use parallel programming.

Any help will be greatly appreciated, thanks a lot!

Eduardo

[Ezo]

..RD2 chip not supported by Willem SW unfortunately

[EduardoLM]

Oh, this is sad.. Thanks for the reply anyway!

Eduardo

[EduardoLM]

Ezo, just a last question, please: all I need is to erase the lock bit on some AT89C51RD2 chips I have. After the lock bit is clear, I can reprogram them using a serial connection.

So, do you think a Willem 3.1, with software 0.97ja can at least clear the lock bit of a AT89C51RD2?

Or do you know any other circuit that could clear the lock bits on this MCU?

Thanks a lot!

Eduardo

[Ezo]

Sorry , no experience on that. More realistic - no.
From experience with ..RD chip not compatible with old version commands, not recognized by willem sw/hw with MCS-51 listed chips.

[EduardoLM]

Thanks for the info, Ezo!

However, I found this on AT89C51RC datasheet today:

"Chip Erase Sequence: Before the AT89C51RC can be reprogrammed, a Chip Erase operation
needs to be performed. To erase the contents of the AT89C51RC, follow this sequence:
1. Raise VCC to 6.5V.
2. Pulse ALE/PROG once (duration of 200 ns - 500 ns) and wait for 150 ms.
3. Power VCC down and up to 6.5V.
4. Pulse ALE/PROG once (duration of 200 ns - 500 ns) and wait for 150 ms.
5. Power VCC down and up."

This is quite easy to implement. And it may work, according to the AT89C51RD2 datasheet:

"Only a full chip erase in parallel mode (using a programmer) or ISP command can reset the soft-
ware security bits."

It seems my problems will be solved if I can do a full erase on my RD2, and luckily the erase procedure doesn't involve any fancy command. I don't even need to worry about address and data buses! All I need to do is to feed the 6.5V and the logic levels to ALE at the correct timings and see what happens.

I will try this in some days and post the results here.

Thanks!

Eduardo

[Ezo]

..RC and RD2 are different chips.
Method of RC erase not applicable for RD2.
No more 6.5V required and SW commands used instead.
---------------
Here is another possibility for checking-
Willem support AT89S in SPI mode (ISP programming)
Select Atmega...>AT89Sxxx> ... with potential similarity of commands.
It takes time to read more documents for understanding - no time today for it.
---------------
Check Atmel Tool FLIP for in-system programming throuhg RS232. It has erase option.

[EduardoLM]

Hi Ezo, thank you very much for your time and patience.

My main problem is that the chip is not going into bootloader mode with the hardware conditions (ALE=floating, /EA=vcc, /PSEN=low during RST lower edge). So, I assume there is some lock bit preventing the chip from entering bootloader.

If I could enter the bootloader, I could use the ISP procedures (and FLIP) to do whatever I wanted with the chip. But in this situation, I'm completely unable to send any ISP command to the chip.

This is why I'm trying the parallel programmer route: my hope is that performing a chip erase will clear the lock bits and allow me to reprogram the chip.

This is sad, but AT89C51RC and AT89S51 datasheets explain exactly how to perform a chip erase on those models, but the AT89C51RD2 datasheet doesn't even touch the subject. I already asked Atmel support, but they don't reply.

Well, thank you again for trying to help, I don't want to bother you, I'm just trying to go deep in this problem, as a learning experience on the enhanced 8051 chips. Even if I don't have success, it's worth the things I'm learning!

Eduardo