RS-232/422/485 Read Hardware FIFO (Composite)

RS-232/422/485 Read Hardware FIFO block


Simulink® Real-Time™ Library for RS-232


The Read Hardware FIFO block reads characters from the I/O module FIFO in the UART.

It then outputs those characters as the low-order byte of an unsigned 32-bit integer vector with a width of 65. This output vector is large enough to hold the maximum number of characters that the FIFO can hold. The first element of the vector specifies the number of data elements in the remainder of the vector.

If the input to the enable port (input port, labeled E) is not true, this block outputs a zero-length vector. The following illustrates the vector.

The UART error status can contain one of the following error values:

0x02 — Overrun error

0x04 — Parity error

0x08 — Framing error

0x01 — Break interrupt

The data byte ranges from 0 to 255.

The dialog box for the RS-232 FIFO Read block contains the following fields.

The Commtech/Fastcom and Quatech® boards and blocks will be removed in a future release. Do not use them in new models. Instead, use boards and blocks available from

Block Parameters

Port (Quatech, Commtech)

From the list, choose a port. This block reads the FIFO from this port.

Flush HW FIFO on startup

Select this check box to flush the FIFO when the device starts up.

Base address (Mainboard, ISA boards)

Enter the base address of the UART for which you want to read the FIFO.

Slot (PCI boards)

If only one board of this type is in the target computer, enter -1 to automatically locate the board.

If two or more boards of this type are in the target computer, enter the bus number and the PCI slot number of the board associated with this driver block. Use the format [BusNumber, SlotNumber]. To determine the bus number and the PCI slot number, type:

tg = slrt;
getPCIInfo(tg, 'installed')

Introduced before R2006a

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