Small doc/example changes

* Use PIO IRQ accessors in PIO I2C example

* Update pio/ir_nec/README.adoc file links (raspberrypi#183)

The "List of Files" now links (only) to files, not to directories (which prevented this example being included in the C SDK databook)

Author: kilograham

i2c/bmp280_i2c/bmp280_i2c.c

@@ -117,7 +117,8 @@ void bmp280_read_raw(int32_t* temp, int32_t* pressure) {
     // note: normal mode does not require further ctrl_meas and config register writes
 
     uint8_t buf[6];
-    i2c_write_blocking(i2c_default, ADDR, (uint8_t*)REG_PRESSURE_MSB, 1, true);  // true to keep master control of bus
+    uint8_t reg = REG_PRESSURE_MSB;
+    i2c_write_blocking(i2c_default, ADDR, &reg, 1, true);  // true to keep master control of bus
     i2c_read_blocking(i2c_default, ADDR, buf, 6, false);  // false - finished with bus
 
     // store the 20 bit read in a 32 bit signed integer for conversion
@@ -184,7 +185,8 @@ void bmp280_get_calib_params(struct bmp280_calib_param* params) {
     // and MSB register, so we read from 24 registers
 
     uint8_t buf[NUM_CALIB_PARAMS] = { 0 };
-    i2c_write_blocking(i2c_default, ADDR, (uint8_t*)REG_DIG_T1_LSB, 1, true);  // true to keep master control of bus
+    uint8_t reg = REG_DIG_T1_LSB;
+    i2c_write_blocking(i2c_default, ADDR, &reg, 1, true);  // true to keep master control of bus
     // read in one go as register addresses auto-increment
     i2c_read_blocking(i2c_default, ADDR, buf, NUM_CALIB_PARAMS, false);  // false, we're done reading
 

pio/i2c/i2c.pio

@@ -108,10 +108,11 @@ static inline void i2c_program_init(PIO pio, uint sm, uint offset, uint pin_sda,
     gpio_set_oeover(pin_scl, GPIO_OVERRIDE_INVERT);
     pio_sm_set_pins_with_mask(pio, sm, 0, both_pins);
 
-    // Clear IRQ flag before starting
-    hw_clear_bits(&pio->inte0, 1u << sm);
-    hw_clear_bits(&pio->inte1, 1u << sm);
-    pio->irq = 1u << sm;
+    // Clear IRQ flag before starting, and make sure flag doesn't actually
+    // assert a system-level interrupt (we're using it as a status flag)
+    pio_set_irq0_source_enabled(pio, pis_interrupt0 + sm, false);
+    pio_set_irq1_source_enabled(pio, pis_interrupt0 + sm, false);
+    pio_interrupt_clear(pio, sm);
 
     // Configure and start SM
     pio_sm_init(pio, sm, offset + i2c_offset_entry_point, &c);

pio/i2c/pio_i2c.c

@@ -13,13 +13,13 @@ const int PIO_I2C_NAK_LSB    = 0;
 
 
 bool pio_i2c_check_error(PIO pio, uint sm) {
-    return !!(pio->irq & (1u << sm));
+    return pio_interrupt_get(pio, sm);
 }
 
 void pio_i2c_resume_after_error(PIO pio, uint sm) {
     pio_sm_drain_tx_fifo(pio, sm);
     pio_sm_exec(pio, sm, (pio->sm[sm].execctrl & PIO_SM0_EXECCTRL_WRAP_BOTTOM_BITS) >> PIO_SM0_EXECCTRL_WRAP_BOTTOM_LSB);
-    pio->irq = 1u << sm;
+    pio_interrupt_clear(pio, sm);
 }
 
 void pio_i2c_rx_enable(PIO pio, uint sm, bool en) {

pio/ir_nec/README.adoc

@@ -26,20 +26,17 @@ After a successful build the executable program can be found in the **build/ir_l
 == List of Files
 
 CMakeLists.txt:: CMake file to incorporate the example in to the examples build tree.
-ir_loopback:: A directory containing the code for the loopback example.
-CMakeLists.txt::: CMake file to incorporate the example in to the examples build tree.
-ir_loopback.c::: The code for the loopback example.
-nec_receive_library:: A directory containing the code for the IR receive functions.
-CMakeLists.txt::: CMake file to incorporate the IR receive library in to the examples build tree.
-nec_receive.c::: The source code for the IR receive functions.
-nec_receive.h::: The headers for the IR receive functions.
-nec_receive.pio::: The PIO assembler code to receive a frame.
-nec_transmit_library:: A directory containing the code for the IR transmit functions.
-CMakeLists.txt::: CMake file to incorporate the IR transmit library in to the examples build tree.
-nec_transmit.c::: The source code for the IR transmit functions.
-nec_transmit.h::: The headers for the IR transmit functions.
-nec_carrier_burst.pio::: The PIO assembler code to generate a carrier burst.
-nec_carrier_control.pio::: The PIO assembler code to transmit a complete frame.
+ir_loopback/CMakeLists.txt:: CMake file to incorporate the loopback example in to the examples build tree.
+ir_loopback/ir_loopback.c:: The code for the loopback example.
+nec_receive_library/CMakeLists.txt:: CMake file to incorporate the IR receive library in to the examples build tree.
+nec_receive_library/nec_receive.c:: The source code for the IR receive functions.
+nec_receive_library/nec_receive.h:: The headers for the IR receive functions.
+nec_receive_library/nec_receive.pio:: The PIO assembler code to receive a frame.
+nec_transmit_library/CMakeLists.txt:: CMake file to incorporate the IR transmit library in to the examples build tree.
+nec_transmit_library/nec_transmit.c:: The source code for the IR transmit functions.
+nec_transmit_library/nec_transmit.h:: The headers for the IR transmit functions.
+nec_transmit_library/nec_carrier_burst.pio:: The PIO assembler code to generate a carrier burst.
+nec_transmit_library/nec_carrier_control.pio:: The PIO assembler code to transmit a complete frame.
 
 == Bill of Materials