Hi,
I am trying to design a circuit in which an EEPROM chip (AT24C01D) can be read/written by both MSP430 micro-controller and external programming tools. As in attached image, I connected the clock and data pins of EEPROM chip to both I2C pins of MSP430 and external programming tool via a connector, I also installed an diode between the VCC pin of EEPROM chip and VCC rail on MSP430, so when the EEPROM chip is being programmed by external tools while MSP430 is shut down, voltage on VCC pin of EEPROM won't power up MSP430.
This design somehow doesn't work. MSP430 is able to read/write EEPROM while external programming tool is not plugged in. But external tool cannot read/write EEPROM even when i remove the diode. However, if I severe SCL and SDA connections between EEPROM and MSP430, then the external programming tool can access EEPROM chip. It seems the connection between EEPROM and MSP430 somehow interferes even when MSP430 is not powered up.
How do I remedy this?
Thanks in advance.
