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UART Interface

The IMX has different UART TTL serial ports. These serial ports can be converted from TTL to RS232 or RS422 using a level converter, such as found on the Rugged-3, EVB-1, and EVB-2 carrier boards.

Actual UART Baud Rates

The serial ports use different peripherals so the actual baud rates of the ports differ.

Due to UART limitations, the actual baud rate that the hardware is capable of generating differs from the target or desired baud rate. This difference is more pronounced at higher baud rates (>921600 bps). The following table outlines these differences.

Target Baud Rate (bps) IMX-5
Actual Baud Rate (bps)
uINS-3
Actual Baud Rate (bps)
19,200 19,198 19,191
38,400 38,406 38,422
57,600 57,595 57,515
115,200 115,273 115,030
230,400 230,547 231,481
460,800 459,770 457,317
921,600 919,540 937,500
3,200,000 3,125,000
4,000,000 3,750,000
5,000,000 4,687,500
8,000,000 6,250,000
10,000,000 9,375,000

IMX-5 UART Baud Rate Equation

The actual baud rate that the IMX-5 hardware is capable of generating is described in the following equation.

Baud rates <= 5 Mbps:

Divisor = floor( (80e6 + ((Target Baud Rate)/2)) / (Target Baud Rate) )
Actual Baud Rate = floor( 80e6 / Divisor )
Baud rates > 5 Mbps:

Divisor = floor( (160e6 + ((Target Baud Rate)/2)) / (Target Baud Rate) )
Actual Baud Rate = floor( 160e6 / Divisor )

uINS-3 UART Baud Rate Equation

The actual baud rate that the IMX-5 hardware is capable of generating is described in the following equations.

Divisor = floor( (18750000 + ((Target Baud Rate)/2)) / (Target Baud Rate) )
Actual Baud Rate = floor( 18750000 / Divisor )