i2c send 2 byte addres - Raspberry Pi Forums

hi community,
putting soft in c ++ need read , write block of data dsp.
these routines read , write in arduino:
//——————————————————————————————————————————————————————————————————————————//
void dsp_write_register_array(uint8_t dspaddress, uint16_t address, byte a, byte b, byte c, byte d)
{
uint8_t addr[] = {address>>8, address&0xff};
uint8_t buf[] = {a,b,c,d};

wire.begintransmission(dspaddress); // begin write
wire.write(addr, 2);
wire.write(buf, 4);
wire.endtransmission(true); // write out data i2c , stop transmitting

delay(10);
}


//——————————————————————————————————————————————————————————————————————————//
void dsp_read_register(uint8_t dspaddress, uint16_t address, uint8_t *data)
{
uint8_t index = 0;
uint8_t addr[] = {address>>8, address&0xff};

wire.begintransmission(dspaddress); // begin write
wire.write(addr, 2); // send internal address want read
wire.endtransmission(false); // write out data i2c don't send stop condition on i2c bus

wire.requestfrom(dspaddress, 4); // request n bytes slave device

while(wire.available()) // slave may send less requested
{
data[index] = wire.read(); // receive byte character
index++;
delay(2);
}
}
can see, write need send 2 bytes command (uint16_t) , array (uint8_t) of 4 data.
use function:
i2c_smbus_write_i2c_block_data(fd, command, size, data);
sends first data of 1 byte , array, solve sending first byte in parameter command , 4 + 1 array data first data second command byte.
functional use, problem comes when have read, when can send data of 1 byte.
tried use function i2c_smbus_write_byte_data(fd, command, data); send first byte , i2c_smbus_read_i2c_block_data(fd, command, size, data); feature opens , closes communication , second function again sends request open communication, not working.
i'm working c ++ libraries colleague made communicate i2c system libraries:
https://github.com/kashimastro/ofxgpio
intention update library in order have more options after solving this.
thank sharing!
greetings!!

raspberrypi