33.6 I/O Lines Programming Example
The programming example shown in the table below is used to obtain the following configurations:
- PIOA Configuration:
- 4-bit output port on Secure I/O lines 0 to 3, open drain, with pull-up resistor
- Four output signals on Non-Secure I/O lines 4 to 7 (to drive LEDs for example), driven high and low, no pull-up resistor, no pull-down resistor
- Secure I/O lines 16 to 19 assigned to peripheral A functions with pull-up resistor
- Non-Secure I/O lines 20 to 23 assigned to peripheral B functions with pull-down resistor
- PIOB Configuration:
- Four input signals on Secure I/O lines 0 to 3 (to read push-button states for example), with pull-up resistors, glitch filters and input change interrupts
- Four input signals on Non-Secure I/O lines 12 to 15 to read an external device status (polled, thus no input change interrupt), no pull-up resistor, no glitch filter
- Secure I/O lines 16 to 23 assigned to peripheral B functions with pull-down resistor
- Non-Secure I/O lines 24 to 27 assigned to peripheral D with Input Change Interrupt, no pull-up resistor and no pull-down resistor
| Action | Register | Value to be Written |
|---|---|---|
| PIOA: Set I/O lines 0 to 3 and 16 to 19 as Secure | S_PIO_SIOSR0 (offset 0x1034) | 0x000F000F |
| PIOA: Set I/O lines 4 to 7 and 20 to 23 as Non-Secure | S_PIO_SIONR0 (offset 0x1030) | 0x00F000F0 |
| PIOA: 4-bit output port on Secure I/O lines 0 to 3, open drain, with pull-up resistor | S_PIO_MSKR0 (offset 0x1000) | 0x0000000F |
| S_PIO_CFGR0 (offset 0x1004) | 0x00004300 | |
| PIOA: Four output signals on Non-Secure I/O lines 4 to 7 (to drive LEDs for example), driven high and low, no pull-up resistor, no pull-down resistor | PIO_MSKR0 (offset 0x0) | 0x000000F0 |
| PIO_CFGR0 (offset 0x4) | 0x00000100 | |
| PIOA: Secure I/O lines 16 to 19 assigned to peripheral A functions with pull-up resistor | S_PIO_MSKR0 (offset 0x1000) | 0x000F0000 |
| S_PIO_CFGR0 (offset 0x1004) | 0x00000201 | |
| PIOA: Non-Secure I/O lines 20 to 23 assigned to peripheral B functions with pull-down resistor | PIO_MSKR0 (offset 0x0) | 0x00F00000 |
| PIO_CFGR0 (offset 0x4) | 0x00000402 | |
| PIOB: Set I/O lines 0 to 3 and 16 to 23 as Secure | S_PIO_SIOSR1 (offset 0x1074) | 0x00FF000F |
| PIOB: Set I/O lines 12 to 15 and 24 to 27 as Non-Secure | S_PIO_SIONR1 (offset 0x1070) | 0x0F00F000 |
| PIOB: Four input signals on Secure I/O lines 0 to 3 (to read push-button states for example), with pull-up resistors, glitch filters and interrupts on rising edge | S_PIO_MSKR1 (offset 0x1040) | 0x0000000F |
| S_PIO_CFGR1 (offset 0x1044) | 0x01001200 | |
| PIOB: Four input signals on Non-Secure I/O lines 12 to 15 to read an external device status (polled, thus no input change interrupt), no pull-up resistor, no glitch filter | PIO_MSKR1 (offset 0x40) | 0x0000F000 |
| PIO_CFGR1 (offset 0x44) | 0x01001200 | |
| PIOB: Secure I/O lines 16 to 23 assigned to peripheral B functions with pull-down resistor | S_PIO_MSKR1 (offset 0x1040) | 0x00FF0000 |
| S_PIO_CFGR1 (offset 0x1044) | 0x00000402 | |
| PIOB: Non-Secure I/O lines 24 to 27 assigned to peripheral D with Input Interrupt on both edges, no pull-up resistor and no pull-down resistor | PIO_MSKR1 (offset 0x40) | 0x0F000000 |
| PIO_CFGR1 (offset 0x44) | 0x02000004 | |
| PIOB: Enable interrupt | S_PIO_IER1 (offset 0x1060) | 0x0000000F |
| PIO_IER1 (offset 0x60) | 0x0F000000 |