Using MOD5270 with Parallax PING
Posted: Fri Nov 14, 2008 2:46 pm
I've got a Parallax PING distance sensor. The input and output are TTL. Should I use a TTL to CMOS interface chip?
The absolute max digital input voltage for the MCF5270 is rated at 4V:
http://www.freescale.com/files/32bit/do ... 5271EC.pdf
The pins are not 5V tolerant. I have recently used a translator that worked pretty well. They are made by TI and have auto-direction sensing. This is nice since which allows for protocols like I2C and also reduces pin count. They are also somewhat cheap (<$1) and provide up to 100Mbit, which is faster then any external signals on this module. You can find them at Digikey.
The part numbers are:
1-bit: TXB0101
2-bit: TXB0102
4-bit: TXB0104
8-bit: TXB0108
-Larry