TXB v/s TXS device selection

Anool Mahidharia

Other Parts Discussed in Thread: TXB0104, TXS0108E, TXS0102

I'm working on a design involving processors at different voltage levels.

1. I need to interface a uSD card with an Atmel ATMega328. Is the TXB0104 a suitable and correct device for such an application ?

2. I need to set up bi-directional communication between a Broadcom BCM2835 processor at 3.3V and the ATMega328 at 5.0V. The communication lines required are :

a. Two wire I2C channel (SDA and SCL)

b. Serial UART channel (Rx and Tx)

c. Two Spare signals from BCM2835 GPIO to the ATMega 328 (to be used, for example, for resetting the ATMega328).

For this, which device family is suitable - TXS or TXB ? You design guide indicates that the TXS series is suitable for I2C applications. Will the same type of device be suitable for Serial UART communications too ? If so, Can I use a single 6 channel device (for #2 a,b,c above) ?

Anool J M

over 13 years ago

0 Junjie Mai over 13 years ago

TI__Expert 4705 points

Hi, Anool,

For your application, I have two solutions. here are they.

1. Using the TXS0108E due to we don't have the 6 channel for TXS parts.

The reason is the TXS0108E can work at both open drian(IC required) and push pull(UART and GPIO required) situation.

The key points you need to check are below.

a. For UART and GPIO interface in BCM2835 outputs, The Vil and Vih of the TXS0108Ecan be met .

b. The Vol and Voh of the TXS0108E are OK for the ATMega328.

c. For UART and GPIO interface, the TXS0108E can support up to 60MBPS, check whether it is Ok for your applicaiton.

2. One TXS0102 for I2C application, and one TXB0104 for UART and GPIO.

The reason is only TXS part can work at the open drain required. but the TXB can not.

Two links here for your reference for the TXB and TXS family application notes. you can get the details for using these two parts. any further thing, please let me know.

BR
Junjie

0 Junjie Mai over 13 years ago in reply to Junjie Mai

TI__Expert 4705 points

Hi, Anool,

Adding the links for applicaiton note.

http://www.ti.com/general/docs/litabsmultiplefilelist.tsp?literatureNumber=scea043

http://www.ti.com/general/docs/litabsmultiplefilelist.tsp?literatureNumber=scea044

Junjie

0 Anool Mahidharia over 13 years ago in reply to Junjie Mai

Prodigy 80 points

Hi, Junjie,

Thanks for that clarification. I was confused because the suggestion I got on the Raspberry-Pi forum was to go for the TXB series device. I'll post back here after we actually test it out.

Logic

Logic forum

TXB v/s TXS device selection