Rename OC i2c files to prevent confusion with micropython files

micropython/modules/lib/micropython.cmake

@@ -11,10 +11,15 @@ target_sources(usermod_opencube_lib INTERFACE
     ${CMAKE_CURRENT_LIST_DIR}/PCF8575.c
     ${CMAKE_CURRENT_LIST_DIR}/ICM42688.h
     ${CMAKE_CURRENT_LIST_DIR}/ICM42688.c
-    ${CMAKE_CURRENT_LIST_DIR}/i2c_master.h
-    ${CMAKE_CURRENT_LIST_DIR}/i2c_master.c
-    ${CMAKE_CURRENT_LIST_DIR}/i2c_slave.h
-    ${CMAKE_CURRENT_LIST_DIR}/i2c_slave.c
+    ${CMAKE_CURRENT_LIST_DIR}/oc_i2c_master.h
+    ${CMAKE_CURRENT_LIST_DIR}/oc_i2c_master.c
+    ${CMAKE_CURRENT_LIST_DIR}/oc_i2c_slave.h
+    ${CMAKE_CURRENT_LIST_DIR}/oc_i2c_slave.c
+)
+
+target_link_libraries(usermod_opencube_lib INTERFACE
+    usermod_opencube_pindefs
+    pico_i2c_slave
 )
 
 # Add the current directory as an include directory.

micropython/modules/lib/oc_i2c_master.c

+#include "hardware/i2c.h"
+
+#include "PCF8575.h"
+#include <opencube_hw.h>
+#include "oc_i2c_master.h"
+
+void opencube_i2c_master_init() {
+    PCF8575_init();
+    PCF8575_write_pin(I2C_STRONG_PULL_RPIN, false); // activate external pull-ups
+
+    gpio_init(UTZ_I2C_SDA_PIN);
+    gpio_set_function(UTZ_I2C_SDA_PIN, GPIO_FUNC_I2C);
+
+    gpio_init(UTZ_I2C_SCK_PIN);
+    gpio_set_function(UTZ_I2C_SCK_PIN, GPIO_FUNC_I2C);
+
+    i2c_init(UTZ_I2C_BUS, MULTICUBE_I2C_BAUD_RATE);
+}
\ No newline at end of file

micropython/modules/lib/oc_i2c_master.h

+/**
+ *  Library for I2C master multicube communication
+ */
+#ifndef OPENCUBE_I2C_MASTER_H
+#define OPENCUBE_I2C_MASTER_H
+
+#endif //OPENCUBE_I2C_MASTER_H
\ No newline at end of file

micropython/modules/lib/oc_i2c_slave.c

+#include <hardware/i2c.h>
+#include <pico/i2c_slave.h>
+#include <pico/stdlib.h>
+
+#include <opencube_hw.h>
+#include "oc_i2c_slave.h"
+#include "PCF8575.h"
+
+// The slave implements a 256 byte memory. To write a series of bytes, the master first
+// writes the memory address, followed by the data. The address is automatically incremented
+// for each byte transferred, looping back to 0 upon reaching the end. Reading is done
+// sequentially from the current memory address.
+static struct
+{
+    uint8_t mem[256];
+    uint8_t mem_address;
+    bool mem_address_written;
+} context;
+
+static void opencube_i2c_slave_handler(i2c_inst_t *i2c, i2c_slave_event_t event);
+
+// Our handler is called from the I2C ISR, so it must complete quickly. Blocking calls /
+// printing to stdio may interfere with interrupt handling.
+static void opencube_i2c_slave_handler(i2c_inst_t *i2c, i2c_slave_event_t event) {
+    switch (event) {
+    case I2C_SLAVE_RECEIVE: // master has written some data
+        if (!context.mem_address_written) {
+            // writes always start with the memory address
+            context.mem_address = i2c_read_byte_raw(i2c);
+            context.mem_address_written = true;
+        } else {
+            // save into memory
+            context.mem[context.mem_address] = i2c_read_byte_raw(i2c);
+            context.mem_address++;
+        }
+        break;
+    case I2C_SLAVE_REQUEST: // master is requesting data
+        // load from memory
+        i2c_write_byte_raw(i2c, context.mem[context.mem_address]);
+        context.mem_address++;
+        break;
+    case I2C_SLAVE_FINISH: // master has signalled Stop / Restart
+        context.mem_address_written = false;
+        break;
+    default:
+        break;
+    }
+}
+
+void opencube_i2c_slave_init(uint8_t address) {
+    PCF8575_init();
+    PCF8575_write_pin(I2C_STRONG_PULL_RPIN, true);
+
+    gpio_init(UTZ_I2C_SDA_PIN);
+    gpio_set_function(UTZ_I2C_SDA_PIN, GPIO_FUNC_I2C);
+
+    gpio_init(UTZ_I2C_SCK_PIN);
+    gpio_set_function(UTZ_I2C_SCK_PIN, GPIO_FUNC_I2C);
+
+    i2c_init(UTZ_I2C_BUS, MULTICUBE_I2C_BAUD_RATE);
+    // configure for slave mode
+    i2c_slave_init(i2c0, address, &opencube_i2c_slave_handler);
+}
+
+// I2C reserves some addresses for special purposes. We exclude these from the scan.
+// These are any addresses of the form 000 0xxx or 111 1xxx
+bool reserved_addr(uint8_t addr) {
+    return (addr & 0x78) == 0 || (addr & 0x78) == 0x78;
+}
\ No newline at end of file

micropython/modules/lib/oc_i2c_slave.h

+/**
+ *  Library for I2C slave multicube communication
+ */
+#ifndef OPENCUBE_I2C_SLAVE_H
+#define OPENCUBE_I2C_SLAVE_H
+
+#endif //OPENCUBE_I2C_SLAVE_H
\ No newline at end of file