Merge pull request #9 from zhengmaxwell/payload

added read and write payload functions

CHANGELOG.md

@@ -1,3 +1,18 @@
+### 0.0.14
+
+* Enable reading and writing a contiguous payload of bytes
+
+### 0.0.13
+
+* Ensure that the system is compiled with I2C support for Teensy 3.2
+
+### 0.0.12
+
+* Preliminary Teensy 4.0 Support
+
+### 0.0.11
+
+* Added the ability to talk to 1 byte register address  I2C devices.
 ### 0.0.10
 
 * Fix spi_transfer_bulk

src/commandconstants.hpp

@@ -22,6 +22,8 @@ int i2c_read_uint8(CommandRouter *cmd, int argc, const char **argv);
 int i2c_read_no_register_uint8(CommandRouter *cmd, int argc, const char **argv);
 int i2c_write_no_register_uint8(CommandRouter *cmd, int argc,
                                 const char **argv);
+int i2c_write_payload(CommandRouter *cmd, int argc, const char **argv);
+int i2c_read_payload(CommandRouter *cmd, int argc, const char **argv);
 
 // PWM Support
 int analog_write(CommandRouter *cmd, int argc, const char **argv);
@@ -80,6 +82,16 @@ command_item_t command_list[] = {
      "Write a uint8_t to the I2C bus without specifying a register address.",
      "i2c_write_no_register_uint8 slave_address data",
      i2c_write_no_register_uint8},
+    {"i2c_write_payload",
+     "Write up to 8 bytes to the I2C bus starting at a specified register "
+     "address.",
+     "i2c_write_payload slave_address register_address data num_bytes",
+     i2c_write_payload},
+    {"i2c_read_payload",
+     "Read up to 8 bytes from the I2C bus starting at a specified register "
+     "address.",
+     "i2c_read_payload slave_address register_address data num_bytes",
+     i2c_read_payload},
     {"analog_write", "Write the duty cycle of the PWM",
      "analog_write pin dutycycle", analog_write},
     {"analog_write_frequency", "Write the frequency of the PWM",

src/i2c.cpp

@@ -85,6 +85,69 @@ int I2CMaster::write_no_register_uint8(int slave_address, uint8_t data) {
   return Wire.getError();
 }
 
+int I2CMaster::write_payload(int slave_address, int register_address,
+                             uint8_t *data, int num_bytes) {
+  if (!this->is_initialized)
+    return ENODEV;
+
+  // Wire library uses 7 bit addresses
+  if (slave_8bit_address)
+    slave_address = slave_address >> 1;
+
+  Wire.beginTransmission(slave_address); // slave addr
+  this->_write_register_address(register_address);
+  Wire.write(data, num_bytes);
+  // blocking write (when not specified I2C_STOP is implicit)
+  Wire.endTransmission(I2C_STOP);
+
+  return Wire.getError();
+}
+
+int I2CMaster::read_payload(int slave_address, int register_address,
+                            uint8_t *data, int num_bytes) {
+  if (!this->is_initialized)
+    return ENODEV;
+  // Wire library uses 7 bit addresses
+  if (slave_8bit_address)
+    slave_address = slave_address >> 1;
+  // Ensure the address is in write mode
+  uint8_t err;
+
+  Wire.beginTransmission(slave_address); // slave addr
+  // Write the MSB of the address first
+  this->_write_register_address(register_address);
+  Wire.endTransmission(
+      I2C_NOSTOP); // blocking write (when not specified I2C_STOP is implicit)
+  err = Wire.getError();
+  if (err) {
+    goto handle_error;
+  }
+
+  Wire.requestFrom(slave_address, num_bytes);
+  Wire.finish();
+  err = Wire.getError();
+  if (err) {
+    goto handle_error;
+  }
+
+  if (Wire.available() != num_bytes) {
+    err = 3;
+    goto handle_error;
+  }
+
+  for (int i = 0; i < num_bytes; i++) {
+    data[i] = Wire.readByte();
+  }
+
+  return 0;
+
+handle_error:
+  while (Wire.available() != 0) {
+    Wire.readByte();
+  }
+  return err;
+}
+
 int I2CMaster::read_uint16(int slave_address, int register_address,
                            uint16_t &data) {
   if (!this->is_initialized)

src/i2c.hpp

@@ -2,9 +2,8 @@
 // only support teensies 3.1, 3.2, 3.5, and 3.6
 // See list of microcontroller units
 // https://docs.platformio.org/en/latest/platforms/teensy.html
-#if defined(TEENSYDUINO) && \
-    (defined(__MK20DX256__) || defined(__MK64FX512__) || \
-     defined(__MK66FX1M0__))
+#if defined(TEENSYDUINO) && (defined(__MK20DX256__) ||                         \
+                             defined(__MK64FX512__) || defined(__MK66FX1M0__))
 #define TEENSY_TO_ANY_HAS_I2C 1
 #else
 #define TEENSY_TO_ANY_HAS_I2C 0
@@ -25,6 +24,10 @@ class I2CMaster {
   int read_uint8(int slave_address, int register_address, uint8_t &data);
   int read_no_register_uint8(int slave_address, uint8_t &data);
   int write_no_register_uint8(int slave_address, uint8_t data);
+  int write_payload(int slave_address, int register_address, uint8_t *data,
+                    int num_bytes);
+  int read_payload(int slave_address, int register_address, uint8_t *data,
+                   int num_bytes);
 
 private:
   void _write_register_address(int register_address);

src/main.cpp

@@ -132,6 +132,67 @@ int i2c_write_uint8(CommandRouter *cmd, int argc, const char **argv) {
 #endif
 }
 
+int i2c_write_payload(CommandRouter *cmd, int argc, const char **argv) {
+#if TEENSY_TO_ANY_HAS_I2C
+  const int num_bytes_max = 8;
+  uint8_t data[num_bytes_max];
+  if (argc < 4)
+    return EINVAL;
+
+  int num_bytes = argc - 3;
+  if (num_bytes > num_bytes_max)
+    return EINVAL;
+
+  int slave_address = strtol(argv[1], nullptr, 0);
+  int register_address = strtol(argv[2], nullptr, 0);
+
+  for (int i = 0; i < num_bytes; i++) {
+    data[i] = strtol(argv[i + 3], nullptr, 0);
+  }
+
+  return i2c.write_payload(slave_address, register_address, data, num_bytes);
+
+#else
+  return -1;
+#endif
+}
+
+int i2c_read_payload(CommandRouter *cmd, int argc, const char **argv) {
+#if TEENSY_TO_ANY_HAS_I2C
+  const int num_bytes_max = 8;
+  if (argc != 4)
+    return EINVAL;
+
+  int slave_address = strtol(argv[1], nullptr, 0);
+  int register_address = strtol(argv[2], nullptr, 0);
+  int num_bytes = strtol(argv[3], nullptr, 0);
+  if (num_bytes > num_bytes_max)
+    return EINVAL;
+
+  uint8_t data[8];
+  int result;
+  result = i2c.read_payload(slave_address, register_address, data, num_bytes);
+
+  if (result == 0) {
+    for (int i = 0; i < num_bytes; i++) {
+      if (i == 0) {
+        snprintf(cmd->buffer, cmd->buffer_size, "0x%02X", data[i]);
+      } else {
+        snprintf(cmd->buffer + strlen(cmd->buffer), cmd->buffer_size, "0x%02X",
+                 data[i]);
+      }
+      if (i != num_bytes - 1) {
+        snprintf(cmd->buffer + strlen(cmd->buffer), cmd->buffer_size, "%c",
+                 ' ');
+      }
+    }
+  }
+  return result;
+#else
+  return -1;
+#endif
+}
+
 int i2c_read_uint16(CommandRouter *cmd, int argc, const char **argv) {
 #if TEENSY_TO_ANY_HAS_I2C
   if (argc != 3)