Ttl level uart interface – ThingMagic Micro Hardware User Manual
Page 23
Hardware Interfaces
A D I V I S I O N O F T R I M B L E
Hardware Overview
23
Note
It is not recommended to use the TTL interface when planning to operate the
module in
Tag Streaming/Continuous Reading
mode. The TTL interface (both the
module side and the host side) cannot detect physical disconnections, as
can the
, simplifying reconnection.
TTL Level UART Interface
TTL Level TX
V-Low: Max 0.4 VDC
V-High: 2.1 to 3.3 VDC
8 mA max
TTL Level RX
V-Low: -0.3 to 0.6 VDC
V-High: 2.2 to 5 VDC
A level converter could be necessary to interface to other devices that use standard 12V
RS232. Only three pins are required for serial communication (TX, RX, and GND).
Hardware handshaking is not supported. The Micro serial port has an interrupt-driven
FIFO that empties into a circular buffer.
The connected host processor’s receiver must have the capability to receive up to 256
bytes of data at a time without overflowing.
Baud rates supported:
– 9600
– 19200
– 38400
– 115200
– 230400
– 460800
– 921600
Note
mode depends on whether the module
entered the bootloader mode after a power-up or through an assert or “boot
bootloader” user command. Upon power up if the
is LOW then the
default baud rate of 115200 will be used. If the module returns to the
bootloader from
mode, then the current state and
baudrate will be retained.