xr

3

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Copyright 2005 EXAR Corporation

January 2005

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You can directly replace the ST16C2550 with the XR16L2750 in the 44-pin PLCC and 48-pin TQFP pack-

ages. In those packages, they are pin-to-pin compatible. If using the ST16C2550 in the 40-pin PDIP pack-

age, then hardware changes will be required since the XR16L2750 is not available in that package.

Since the internal registers of the XR16L2750 are the same as the ST16C2550, the XR16L2750 will work

with the same driver that is used with the ST16C2550 without any changes. However, to take advantage

of the enhanced features in the XR16L2750 such as the larger FIFO, Programmable Trigger Levels, FIFO

Level Counters, Auto Hardware Flow Control, Auto Software Flow Control and RS-485 Half-Duplex Con-

trol, the existing software needs to be modified.

In a nutshell, the ST16C2550 and XR16L2750 are very similar devices but with different FIFO sizes and

the XR16L2750 has some addtional features not found in the ST16C2550.