I'm trying to use the serial bootloader/ISP mode in the Atmel AT89C51RC, but haven't had any luck getting the bootloader to respond. The oscillator is running, and I have EA tied high, PSEN tied low, and ALE open. According to the Atmel documentation, this should cause the chip to enter bootloader mode. However, I'm not getting any response. I've verified that I'm sending 0x55 ('U') to the RXD pin, and I've tried several baud rate and crystal combinations, all which should auto-baud correctly. The Atmel "FLIP" software does not synchronize with the device, either.

Has anyone successfully used this part in serial bootloader mode?

The documentation seems to suggest that the bootloader is built into ROM and automatically runs when a new (blank) device is powered up. Is this true, or does the bootloader need to be loaded into flash memory?

Thanks for any suggestions!

-Jeff