some example rationalization and readme cleanup

Author: kilograham

README.md

@@ -304,28 +304,31 @@ App|Description
 App|Description
 ---|---
 [hello_pio](pio/hello_pio) | Absolutely minimal example showing how to control an LED by pushing values into a PIO FIFO.
-[apa102](pio/apa102) | Rainbow pattern on on a string of APA102 addressable RGB LEDs.
-[clocked_input](pio/clocked_input) | Shift in serial data, sampling with an external clock.
-[differential_manchester](pio/differential_manchester) | Send and receive differential Manchester-encoded serial (BMC).
-[hub75](pio/hub75) | Display an image on a 128x64 HUB75 RGB LED matrix.
-[i2c](pio/i2c) | Scan an I2C bus.
-[ir_nec](pio/ir_nec) | Sending and receiving IR (infra-red) codes using the PIO.
-[logic_analyser](pio/logic_analyser) | Use PIO and DMA to capture a logic trace of some GPIOs, whilst a PWM unit is driving them.
-[manchester_encoding](pio/manchester_encoding) | Send and receive Manchester-encoded serial.
-[onewire](pio/onewire)| A library for interfacing to 1-Wire devices, with an example for the DS18B20 temperature sensor.
+[pio_apa102](pio/apa102) | Rainbow pattern on on a string of APA102 addressable RGB LEDs.
+[pio_clocked_input](pio/clocked_input) | Shift in serial data, sampling with an external clock.
+[pio_differential_manchester](pio/differential_manchester) | Send and receive differential Manchester-encoded serial (BMC).
+[pio_hub75](pio/hub75) | Display an image on a 128x64 HUB75 RGB LED matrix.
+[pio_i2c_bus_scan](pio/i2c) | Scan an I2C bus.
+[pio_ir_loopback](pio/ir_nec) | Sending and receiving IR (infra-red) codes using the PIO.
+[pio_logic_analyser](pio/logic_analyser) | Use PIO and DMA to capture a logic trace of some GPIOs, whilst a PWM unit is driving them.
+[pio_manchester_encoding](pio/manchester_encoding) | Send and receive Manchester-encoded serial.
+[pio_onewire](pio/onewire)| A library for interfacing to 1-Wire devices, with an example for the DS18B20 temperature sensor.
 [pio_blink](pio/pio_blink) | Set up some PIO state machines to blink LEDs at different frequencies, according to delay counts pushed into their FIFOs.
-[pwm](pio/pwm) | Pulse width modulation on PIO. Use it to gradually fade the brightness of an LED.
-[spi](pio/spi) | Use PIO to erase, program and read an external SPI flash chip. A second example runs a loopback test with all four CPHA/CPOL combinations.
-[squarewave](pio/squarewave) | Drive a fast square wave onto a GPIO. This example accesses low-level PIO registers directly, instead of using the SDK functions.
-[squarewave_div_sync](pio/squarewave) | Generates a square wave on three GPIOs and synchronises the divider on all the state machines
-[st7789_lcd](pio/st7789_lcd) | Set up PIO for 62.5 Mbps serial output, and use this to display a spinning image on a ST7789 serial LCD.
+[pio_pwm](pio/pwm) | Pulse width modulation on PIO. Use it to gradually fade the brightness of an LED.
 [quadrature_encoder](pio/quadrature_encoder) | A quadrature encoder using PIO to maintain counts independent of the CPU. 
 [quadrature_encoder_substep](pio/quadrature_encoder_substep) | High resolution speed measurement using a standard quadrature encoder
-[uart_rx](pio/uart_rx) | Implement the receive component of a UART serial port. Attach it to the spare Arm UART to see it receive characters.
-[uart_tx](pio/uart_tx) | Implement the transmit component of a UART serial port, and print hello world.
-[ws2812](pio/ws2812) | Examples of driving WS2812 addressable RGB LEDs.
-[addition](pio/addition) | Add two integers together using PIO. Only around 8 billion times slower than Cortex-M0+.
+[pio_spi_flash](pio/spi) | Use PIO to erase, program and read an external SPI flash chip
+[pio_spi_loopback](pio/spi) | Use PIO to run a loopback test with all four CPHA/CPOL combinations.
+[pio_squarewave](pio/squarewave) | Drive a fast square wave onto a GPIO. This example accesses low-level PIO registers directly, instead of using the SDK functions.
+[pio_squarewave_div_sync](pio/squarewave) | Generates a square wave on three GPIOs and synchronises the divider on all the state machines
+[pio_st7789_lcd](pio/st7789_lcd) | Set up PIO for 62.5 Mbps serial output, and use this to display a spinning image on a ST7789 serial LCD.
 [uart_pio_dma](pio/uart_pio_dma) | Send and receive data from a UART implemented using the PIO and DMA
+[pio_uart_rx](pio/uart_rx) | Implement the receive component of a UART serial port. Attach it to the spare Arm UART to see it receive characters.
+[pio_uart_rx_intr](pio/uart_rx) | Implement the receive component of a UART serial port with an interrupt for received characters. Attach it to the spare Arm UART to see it receive characters.
+[pio_uart_tx](pio/uart_tx) | Implement the transmit component of a UART serial port, and print hello world.
+[pio_ws2812](pio/ws2812) | Example of driving a string WS2812 addressable RGB LEDs.
+[pio_ws2812_parallel](pio/ws2812) | Examples of driving multiple strings of WS2812 addressable RGB LEDs efficiently.
+[pio_addition](pio/addition) | Add two integers together using PIO. Only around 8 billion times slower than Cortex-M0+.
 
 ### PWM
 

pio/CMakeLists.txt

@@ -17,10 +17,10 @@ if (TARGET hardware_pio)
     add_subdirectory_exclude_platforms(spi)
     add_subdirectory_exclude_platforms(squarewave)
     add_subdirectory_exclude_platforms(st7789_lcd)
+    add_subdirectory_exclude_platforms(uart_dma)
     add_subdirectory_exclude_platforms(uart_rx)
     add_subdirectory_exclude_platforms(uart_tx)
     add_subdirectory_exclude_platforms(ws2812)
-    add_subdirectory_exclude_platforms(uart_pio_dma)
 else()
     message("Skipping PIO examples as hardware_pio is unavailable on this platform")
 endif()

pio/ir_nec/nec_receive_library/CMakeLists.txt

@@ -1,19 +1,20 @@
-# build a normal library
-#
-add_library(nec_receive_library nec_receive.c)
+add_library(nec_receive_library INTERFACE)
+
+target_sources(nec_receive_library INTERFACE
+		${CMAKE_CURRENT_LIST_DIR}/nec_receive.c)
 
 # invoke pio_asm to assemble the state machine program
 #
 pico_generate_pio_header(nec_receive_library ${CMAKE_CURRENT_LIST_DIR}/nec_receive.pio)
 
-target_link_libraries(nec_receive_library PRIVATE
+target_link_libraries(nec_receive_library INTERFACE
         pico_stdlib
         hardware_pio
         )
 
 # add the `binary` directory so that the generated headers are included in the project
 #
-target_include_directories (nec_receive_library PUBLIC
+target_include_directories (nec_receive_library INTERFACE
 	${CMAKE_CURRENT_SOURCE_DIR}
 	${CMAKE_CURRENT_BINARY_DIR}
 	)

pio/ir_nec/nec_transmit_library/CMakeLists.txt

@@ -1,20 +1,21 @@
-# build a normal library
-#
-add_library(nec_transmit_library nec_transmit.c)
+add_library(nec_transmit_library INTERFACE)
+
+target_sources(nec_transmit_library INTERFACE
+		${CMAKE_CURRENT_LIST_DIR}/nec_transmit.c)
 
 # invoke pio_asm to assemble the PIO state machine programs
 #
 pico_generate_pio_header(nec_transmit_library ${CMAKE_CURRENT_LIST_DIR}/nec_carrier_burst.pio)
 pico_generate_pio_header(nec_transmit_library ${CMAKE_CURRENT_LIST_DIR}/nec_carrier_control.pio)
 
-target_link_libraries(nec_transmit_library PRIVATE
+target_link_libraries(nec_transmit_library INTERFACE
         pico_stdlib
         hardware_pio
         )
 
 # add the `binary` directory so that the generated headers are included in the project
 #
-target_include_directories (nec_transmit_library PUBLIC
+target_include_directories (nec_transmit_library INTERFACE
 	${CMAKE_CURRENT_SOURCE_DIR}
 	${CMAKE_CURRENT_BINARY_DIR}
 	)

pio/uart_dma/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_executable(pio_uart_dma)
+pico_generate_pio_header(pio_uart_dma ${CMAKE_CURRENT_LIST_DIR}/../uart_rx/uart_rx.pio)
+pico_generate_pio_header(pio_uart_dma ${CMAKE_CURRENT_LIST_DIR}/../uart_tx/uart_tx.pio)
+target_sources(pio_uart_dma PRIVATE uart_dma.c)
+target_link_libraries(pio_uart_dma PRIVATE
+        pico_stdlib
+        hardware_pio
+        hardware_dma
+        )
+pico_add_extra_outputs(pio_uart_dma)
+example_auto_set_url(pio_uart_dma)