Electrical interface
More detailed information can be found in the relevant datasheet.
Connectors
The TapNLink modules have 3 connectors:
- P1 extension connector, composed of two rows (P1A and P1B) of contacts.
- J1 connects the TAP to the target board's debug connector (ARM-SWD standard).
- J3 connects the TAP to the target board (it is a subset of J1). We recommend you move CLK (SWDCLK) away from DATA (SWDIO). Do not use a ribbon cable with these two signals adjacent. This pdf shows a wiring that has been tested with a 150cm cable.
Cable
The cable between the Tap and the application board must be less than 1 meter (the shorter, the better). You must guard against electromagnetic interference, and you may have to use a shielded cable.
Electrical characteristics
The TAP signals are connected to the main microcontroller via a 22 ohm resistance:
The power source is lowered by a diode (NSR20F30) (typically 250 mV drop) to allow NFC to provide the power supply.
Note: Full Energy harvesting is only available for the NFC-only module (ref TnL-FIT203).
The applicable voltage levels are those of the main MCU (STM32L432K).
| Symbol | Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Vtarget(1) | Voltage supplied by target | 2 | 3 | 3.5 | V |
| VIL | I/O signals input low level | - | 0.25xVcc(2) | V | |
| VIH | I/O signals input high level | 0.75xVcc(2) | V | ||
| VOH | Output high level voltage for I/O signals | 0.8xVcc | - | V | |
| VOL | Output low level voltage for I/O signals | - | 0.35xVcc | ||
| ICC | Current supplied by target | 10mA | 15mA | 18mA | mA |
-
Vtarget is the voltage supplied by the application board (the target) at the J1/J3 connector.
-
VCC is the TAP voltage (typically Vcc = Vtarget – 250mV).