Bootloader Cypress EZ-USB question

I've just started using the KEIL product with Cypress EZ-USB FX development kit. The EZUSB core supports a sort of bootstrap loader on the I2C interface. If you use B6 for the first byte in a serial eeprom device, it looks like the core will copy records of a certain format into memory. However, it limits 8051 program/data space that can be written to 0x1b3f.

Two questions. 1) why the limitation? The core also supports a specific vendor request (bRequest A0, Control EP0 IN and OUT) that can write or read to seemingly any external memory space.

2) Is it possible to write a loader app that can be loaded by the core at power up, interrogate the rest of the I2C device, load external ram and then transfer control to exteral program now loaded? The idea being that even though it's easy to soft load the EZ-USB device, you could run a whole program loaded from the I2C serial eeprom.

Parents
  • Rob,

    I am also about to start using the Cypress EZ-USB development kit (although not the FX, for the 2100 series). I think the 1b3f limitatioin is just on internal code space, you can have up to the full 64K of external memory space.

    It seems like what you're asking should be possible, you may have to do some logic with PSEN, RD and WR.

    I have a question for you: How do you get your code from the Keil compiler into the I2C EEPROM without the USB link? I know that you just have to bring SDA and SCL to the outside world and they are available on the development board but is there some kind of an I2C EEPROM programmer?

    Mike

Reply
  • Rob,

    I am also about to start using the Cypress EZ-USB development kit (although not the FX, for the 2100 series). I think the 1b3f limitatioin is just on internal code space, you can have up to the full 64K of external memory space.

    It seems like what you're asking should be possible, you may have to do some logic with PSEN, RD and WR.

    I have a question for you: How do you get your code from the Keil compiler into the I2C EEPROM without the USB link? I know that you just have to bring SDA and SCL to the outside world and they are available on the development board but is there some kind of an I2C EEPROM programmer?

    Mike

Children
More questions in this forum