We're designing an interface card (shield) for the Raspberry-Pi (Broadcom BCM2835 ARM processor). Our shield is based on the Atmel ATMega processor (ATMega328P). We will have two communication interfaces between the ARM processor at 3.3 V and the ATMega processor at 5V.
1. Two wire I2C using SDA and SCL
2. Serial communication using UART (Rx, Tx and GND).
3. Finally, we need two spare interface signals from the ARM GPIO to the ATMega. These may be used to reset the ATMega, for example.
That's a total of 6 signals between the ARM GPIO pins and the ATMega.
Can you clarify which specific voltage translation device would be suitable ? The application notes recommend a TXS type device for I2C applications. Can the same type of device be used for serial UART application ?
We will also have a uSD card interfaced to the ATMega. For uSD interface, please confirm if the TXB0104 is suitable.
Anool J M : email@example.com