TL16C754B: Is this device 16550 Standard compliant

Hi Praveen,

I apologize for the delay in responding to your question while I did a little research. I wanted to make sure I gave you a correct answer.

I believe that I can safely determine that the TL16C754B is 16550 compliant and a good option to suggest to the customer.

The UART device family has evolved from the 8250 devices with an interrupt after every byte to the 16450 with FIFOs to cut down on the number of interrupts. However, there was a firmware bug in the 16450 preventing the FIFO's from being accessed which was then fixed in the 16550 family and increased the FIFOs to 16bytes. Then came the 16650 Family with 32byte FIFOs and additional features above the 16550 capabilities. And now there is also the 16750 family of devices that have 64byte FIFOs and even more enhanced features than both the 16550 and 16650 devices. I don't have personal experience with designing systems around each of these versions of UARTs but it is my understanding that at the core, all the newer versions are compatible with the traditional 16550 standard operation even if the "enhanced features" are not used.

Taking the TL16C550B as a device that is safe to call 16550 Compliant as our standard reference, the TL16C554 / TL16554I devices are described in the first sentence of the description in their datasheet as "enhanced quadruple versions of the TL16C550B asynchronous communications element (ACE)." There are also pin for pin compatible devices to the TL16C554 device from other semiconductor companies, so it is safe to say the TL16C554 device can be regarded as a standard device that is commonly used.

You are interested in the TL16C754B device which is a 16750 device. The first paragraph of the Functional Description of the datasheet on page 5 says:

"The TL16C754B UART is pin compatible with the TL16C554 and ST16C654 UARTS. It provides more enhanced features. All additional features are provided through a special enhanced feature register."

The ST16C654 is a competitive device of the 16650 family with 32 byte FIFOs which was improved upon with the TL16C754 device. And I'm not sure how far your definition of "16550 compliance" extends and whether that is just for functionality, or also for package and pinouts. But the TL16C754 is pin compatible with both the TL16C554 and SC16C654 devices for the FN packages.

I would hope some of the enhanced features like 64byte FIFOs of the TL16754B could be implemented by the customer, but this device could be used in a traditional 16550 application since the core registers (0-7) are the same.

I hope this answers your question.

Regards,
Jonathan