MSC SM2S-IMX8M User Manual
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4.12 UART
The i.MX8M offers several UART interfaces. Depending on module variant up to f
our separate interfaces are linked to the SMARC™ connector, two
of them with Hardware flow control support signals.
The UART interfaces supports Serial RS-232NRZ mode, 9-bit RS-485 mode or IrDA mode and includes the following features amongst others:
•
High-speed TIA/EIA-232-F compatible, up to 5.0 Mbit/s
•
Serial IR interface low-speed, IrDA-compatible (up to 115.2 Kbit/s)
•
9-bit or Multidrop mode (RS-485) support (automatic slave address detection)
•
7 or 8 data bits for RS-232 characters, or 9 bit RS-485 format
•
1 or 2 stop bits
•
Programmable parity (even, odd, and no parity)
•
Hardware flow control support for request to send (RTS_B) and clear to send (CTS_B) signals
•
RS-485 driver direction control via CTS_B signal
•
Edge-selectable RTS_B and edge-detect interrupts
•
Status flags for various flow control and FIFO states
•
Voting logic for improved noise immunity (16x oversampling)
•
Transmitter FIFO empty interrupt suppression
•
UART internal clocks enable/disable
•
Auto baud rate detection (up to 115.2 Kbit/s)
•
Receiver and transmitter enable/disable for power saving
•
RX_DATA input and TX_DATA output can be inverted respectively in RS-232/RS-485 mode
•
Maskable interrupts
•
Two DMA Requests (TxFIFO DMA Request and RxFIFO DMA Request)
•
Escape character sequence detection
•
Software reset (SRST_B)
•
Two independent, 32-entry FIFOs for transmit and receive
Table 4-12: UART Signal Description
Signal
Pin Type
Signal
Level
Pin on
i.MX8M
Pin name on
i.MX8M
Power
Toleranc
e
PU/PD
Description
SER0_TX
O
1.8V CMOS
A7
UART1_RXD
1.8V
PU 10k 1.8V
UART transmit data (also see Note 1 below!)
SER0_RX
I
1.8V CMOS
C7
UART1_TXD
1.8V
PU 10k 1.8V
UART receive data (also see Note 1 below!)