This is a Tibbit module — part of the Tibbo Project System that allows you to build your own custom embedded device with only the components you need. Start with a Tibbo Project PCB, add Tibbits like this one, then place the built design into a Tibbo Project Box to complete your product.
Tibbit #05: RS485 port with full-duplex or half-duplex operation.
This port has only +/-RX and +/-TX signal pairs. If you are working in the half-duplex mode, connect +RX to +TX, and -RX to -TX. This will allow your system to communicate over a single twisted pair. Direction control is through the RTS line — the line shall be LOW for data input and HIGH for output. Keep the RX and TX pairs separate for the full-duplex mode and set the RTS line HIGH to keep the TX enabled at all times.
For "normal" RS485 applications, this Tibbit has to be connected to the TX and RX lines of the CPU's UART (see [SER]).
Combine this Tibbit with a terminal block C Tibbit #20 (nine terminal blocks) or #21 (four terminal blocks).
There are three LEDs. Red LEDs are connected to the TX and OUT/-IN lines. A green LED is for the RX input. All LEDs are buffered (with logic gates) and light up for the LOW state of the control lines.
- Form: M1S
- Power: 5V; consumes 15mA
- Special lines: [SER]
- Mates with: #19, #20, #21
- Similar to: #01, #02
M1S Tibbit Modules Overview M1S Tibbits are single-width modules occupying one standard M socket on a Tibbo Project PCB (i.e. TPP2 or TPP3). Their footprint is roughly 7 × 14 "squares" (one "square" is 2.54 × 2.54 mm). The M1S modules are 12.5mm high.
M1 modules have two rows of 6 pins:
Pins 8-11 are control lines A-D. They provide the interface to programmable modules or other microcontrollers. On Tibbo Project PCBs, these pins are connected to the main processor.
Pins 2-5 are I/O lines facing the outside world. On Tibbo Project PCBs, they go to C Tibbits.
Pins 6 and 12 are the GROUND and +5V power pins. Most Tibbit Modules consume (take) 5V power. There are also power supply Tibbits that generate 5V power from a variety of sources. Those output 5V through pin 12.
Pins 1 and 7 are for the additional +15V and -15V voltages. These are optional and only needed by few Tibbits. A special power supply Tibbit (#12) generates ±15V from the main 5V power.