3.1 Bare Metal Implementation

Do not generate any waveform from the TCE In Pattern Generation mode, so the Pattern Generation Mode bit field in the CTRLA register must be configured accordingly.
```
WEX0.CTRLA = WEX_PGM_bm;
```
Figure 3-1. CTRLA Register
Every signal output must be enabled to be overridden in Pattern Generation mode. Every signal has a one-to-one relationship with the bits from PGMOVR register.
```
WEX0.PGMOVR  = WEX_PGMOVR0_bm | WEX_PGMOVR1_bm | WEX_PGMOVR2_bm | WEX_PGMOVR3_bm | 
                        WEX_PGMOVR4_bm | WEX_PGMOVR5_bm | WEX_PGMOVR6_bm | WEX_PGMOVR7_bm;
```
Figure 3-2. Pattern Generation Override Register
The PGMOUT register holds the pattern for every signal. It is worth mentioning that this every signal has a one-to-one relationship with the bits from PGMOUT register. For example, if pattern 0xAA is desired the following set must be done in the PGMOUT register (set bits 1, 3, 5, 7 bits to high ‘1’ logic):
```
WEX0.PGMOUT = WEX_PGMOUT1_bm | WEX_PGMOUT3_bm | WEX_PGMOUT5_bm | WEX_PGMOUT7_bm;
```
Figure 3-3. Pattern Generation Output Register
After the WEX is configured in Pattern Generation mode, the user can toggle each signals state using the buffer register.
```
WEX0.PGMOUT = ~WEX0.PGMOUT;
```
A delay is added to see when the toggling occurs.
```
_delay_us(25);
```
Port A pins 0-7 (PA0-7) are set as outputs by writing a ‘1’ to the corresponding bits in the Direction register of the port. These GPIOs are configured only to obtain a visible output.
```
PORTA.DIRSET = PIN0_bm | PIN1_bm | PIN2_bm | PIN3_bm |
                        PIN4_bm | PIN5_bm | PIN6_bm | PIN7_bm;
```
Make a setting in the PORTMUX to select the default PORT A pins.
```
PORTMUX.TCEROUTEA = 0x0;
```
Figure 3-4. WEX PORTMUX
Enable the WEX’s outputs by setting the corresponding bits in the Output Override Enable register to enable the PORT A pins override.
```
WEX0.OUTOVEN = WEX_OUTOVEN0_bm | WEX_OUTOVEN1_bm | WEX_OUTOVEN2_bm | WEX_OUTOVEN3_bm |
                        WEX_OUTOVEN4_bm | WEX_OUTOVEN5_bm | WEX_OUTOVEN6_bm | WEX_OUTOVEN7_bm;
```
Figure 3-5. Output Override Enable Register
The last step for this example is to enable the TCE module because the source clock that passes from TCE to WEX is needed for the update of the defined patterns.
```
TCE0.CTRLA = TCE_ENABLE_bm;
```