-- Title: i2c2_hardware
-- Author: Joep Suijs, Copyright (C) 2008 Joep Suijs
-- Adapted for second bus by David VB (2025)
-- Compiler: >=2.4g
--
-- This file is part of jallib (https://github.com/jallib/jallib)
-- Released under the ZLIB license (http://www.opensource.org/licenses/zlib-license.html)
--
-- Description: Level1 implementation of I2C (single) master.
--
-- User must define the rx and tx buffer like:
--    var byte i2c2_tx_buffer[10]
--    var byte i2c2_rx_buffer[10]
--
-- tx_buffer[] should be at least 2 bytes long to support i2c2_receive_wordaddr.
-- if you desperatly want to use a 1-byte tx buffer, define (besides the buffer):
-- const i2c2_single_byte_tx_buffer = 1
--

-- some validations
if (defined(i2c2_single_byte_tx_buffer) ==  false) then
   if (count(i2c2_tx_buffer) < 2) then
      _error "Please make i2c2_tx_buffer[] at least 2 bytes long"
   end if
end if

-- -----------------------------------------------------------------------------
-- i2c2_send_receive - send a string to an i2c slave and receive bytes back
-- -----------------------------------------------------------------------------
-- This funtion uses two global i2c buffers, one for transmit (tx) and one for
-- receive (rx). The address of the slave (higher 7 bits), number of bytes to
-- transmit and number of bytes to receive are parameters.
-- returns true if all went well.
-- -----------------------------------------------------------------------------
function i2c2_send_receive(byte in i2c2_address, byte in i2c2_tx_count, byte in i2c2_rx_count) return bit is
   var byte i
   var bit r = true -- okay

   if ((i2c2_tx_count == 0) & (i2c2_rx_count == 0)) then return false end if
   -- send START and i2c device address for write
   i2c2_start()

   if (i2c2_tx_count > 0) then
      r = i2c2_transmit_byte(i2c2_address & 0xFE)
      if (r == false) then i2c2_stop() return false end if

      -- write data
      for i2c2_tx_count using i loop
         r = r & i2c2_transmit_byte(i2c2_tx_buffer[i])
         if (r == false) then i2c2_stop() return false end if
      end loop

      -- if we also need to receive
      if (i2c2_rx_count > 0) then

         -- send RESTART & i2c2 device address for read
         i2c2_restart()
      end if
   end if

   if (i2c2_rx_count > 0) then
      r = r & i2c2_transmit_byte(i2c2_address | 0x01)
      if (r == false) then i2c2_stop() return false end if

      if (i2c2_rx_count > 1) then
         for (i2c2_rx_count-1) using i loop
            i2c2_rx_buffer[i] = i2c2_receive_byte(true)
         end loop
      end if

      -- read with NACK, to signal it is the last byte.
      i2c2_rx_buffer[i2c2_rx_count-1] = i2c2_receive_byte(false)
   end if

   -- send STOP to end communication sequence with device.
   i2c2_stop()

   return true;   // signal succes

end function



-- -----------------------------------------------------------------------------
-- i2c2_receive_byteaddr - send a byte address and receive a string from an i2c slave
-- -----------------------------------------------------------------------------
function i2c2_receive_byteaddr(byte in i2c2_address, byte in addr, byte in i2c2_rx_count) return bit is

   i2c2_tx_buffer[0] = addr
   return i2c2_send_receive(i2c2_address, 1, i2c2_rx_count)

end function


if (defined(i2c2_single_byte_tx_buffer) == false) then -- conditional compile
-- -----------------------------------------------------------------------------
-- i2c2_receive_wordaddr - send a word address and receive a string from an i2c slave
-- -----------------------------------------------------------------------------
function i2c2_receive_wordaddr(byte in i2c2_address, word in addr, byte in i2c2_rx_count) return bit is

   i2c2_tx_buffer[0] = byte(addr >> 8)
   i2c2_tx_buffer[1] = byte(addr & 0xFF)
   return i2c2_send_receive(i2c2_address, 2, i2c2_rx_count)

end function
end if -- conditional compile