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authorLoek Le Blansch <loek@pipeframe.xyz>2024-06-24 14:04:06 +0200
committerLoek Le Blansch <loek@pipeframe.xyz>2024-06-24 14:04:06 +0200
commit07e49bbbd3790a95511d68b94d47bf107a5e24a1 (patch)
tree805007e6d2f192f849dda163bb04fb6d78e3c801 /lib/pbdrv/drv
parentf6f79683d6ffcc8542652e2eb11a1148d2a94288 (diff)
re-implement deferred I2C handlers for the Arduino pbdrv drv
Diffstat (limited to 'lib/pbdrv/drv')
-rw-r--r--lib/pbdrv/drv/arduino/include.cmake4
-rw-r--r--lib/pbdrv/drv/arduino/index.dox4
-rw-r--r--lib/pbdrv/drv/arduino/mod.cpp51
3 files changed, 46 insertions, 13 deletions
diff --git a/lib/pbdrv/drv/arduino/include.cmake b/lib/pbdrv/drv/arduino/include.cmake
index 520bfc1..5ec1124 100644
--- a/lib/pbdrv/drv/arduino/include.cmake
+++ b/lib/pbdrv/drv/arduino/include.cmake
@@ -5,3 +5,7 @@ endif()
target_sources(pbdrv-mod PRIVATE "${CMAKE_CURRENT_LIST_DIR}/mod.cpp")
target_link_arduino_libraries(pbdrv-mod PRIVATE core Wire)
+# freertos is used to defer the handling of i2c messages outside the receive
+# interrupt service routine
+include("${CMAKE_CURRENT_LIST_DIR}/../../ext/freertos/include.cmake")
+
diff --git a/lib/pbdrv/drv/arduino/index.dox b/lib/pbdrv/drv/arduino/index.dox
index 1856918..03510dd 100644
--- a/lib/pbdrv/drv/arduino/index.dox
+++ b/lib/pbdrv/drv/arduino/index.dox
@@ -10,12 +10,14 @@ This driver is known to work with the following MCUs:
\par Usage
- Link the \c pbdrv-mod library with your main executable
-- Load an \ref pb_ext "extension"
\note This driver is automatically enabled if the variable \c ARDUINO is
defined in your CMakeLists.txt (it is by default when using
Arduino-CMake-Toolchain).
+\note This driver automatically includes the \ref pb_ext_freertos
+"FreeRTOS extension" for deferring calls to \c pb_i2c_recv() from the I2C ISR.
+
A complete example for this driver is available in the \ref puzzle/dummy
folder.
diff --git a/lib/pbdrv/drv/arduino/mod.cpp b/lib/pbdrv/drv/arduino/mod.cpp
index d2a6402..c381077 100644
--- a/lib/pbdrv/drv/arduino/mod.cpp
+++ b/lib/pbdrv/drv/arduino/mod.cpp
@@ -1,22 +1,33 @@
-#ifndef ARDUINO
-#error This driver only works on the Arduino platform!
-#endif
-
#include <Arduino.h>
#include <Wire.h>
#include <avr/delay.h>
+#include <FreeRTOS.h>
+#include <timers.h>
+#include <task.h>
+
#include "../../pb.h"
#include "../../pb-mod.h"
#include "../../pb-types.h"
+#include "../../pb-buf.h"
+#include "../../pb-mem.h"
+
+static void async_pb_i2c_recv(void * _msg, uint32_t _) {
+ pb_buf_t * msg = (pb_buf_t *) _msg;
+ pb_i2c_recv((uint8_t *) msg->data, msg->size);
+ pb_buf_free(msg);
+ pb_free(msg);
+}
static void recv_event(int bytes) {
- uint8_t data[bytes];
- size_t sz = 0;
+ pb_buf_t * msg = (pb_buf_t *) pb_malloc(sizeof(pb_buf_t));
+ msg->data = (char *) pb_malloc(bytes);
+ msg->size = 0;
while (Wire.available())
- data[sz++] = Wire.read();
+ msg->data[msg->size++] = Wire.read();
- pb_i2c_recv(data, sz);
+ // defer pb_i2c_recv call
+ xTimerPendFunctionCallFromISR(async_pb_i2c_recv, msg, 0, NULL);
}
static void pb_setup() {
@@ -27,7 +38,17 @@ static void pb_setup() {
Wire.onReceive(recv_event);
}
+/**
+ * \ingroup pb_drv_arduino
+ * \warning This function includes a hard-coded 10ms delay before sending. This
+ * is to work around a weird issue where the Arduino pulls both SDA and SCL low
+ * while attempting to initiate an I2C transmission. We were able to verify
+ * that the Arduino correctly handles bus arbitration under a test scenario
+ * with 2 Uno's, but ran into issues while integrating the Arduino's with the
+ * RP2040.
+ */
__weak void pb_i2c_send(i2c_addr_t addr, const uint8_t * buf, size_t sz) {
+ vTaskDelay(10 / portTICK_PERIOD_MS); // prevent bus collisions
Wire.beginTransmission((int) addr);
Wire.write(buf, sz);
Wire.endTransmission(true);
@@ -41,6 +62,14 @@ extern void loop(void);
//! Arduino internal initialization
void init(void);
+//! FreeRTOS loop task
+void loop_task() {
+ for(;;) {
+ loop();
+ if (serialEventRun) serialEventRun();
+ }
+}
+
/**
* \ingroup pb_drv_arduino
* \brief Application entrypoint
@@ -59,10 +88,8 @@ int main(void) {
init(); // call arduino internal setup
setup(); // call regular arduino setup
pb_setup(); // call pbdrv-mod setup
- for(;;) {
- loop();
- if (serialEventRun) serialEventRun();
- }
+ xTaskCreate((TaskFunction_t) loop_task, "loop", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL);
+ vTaskStartScheduler(); // start freertos scheduler
return 0;
}