-- MCP23017 I2C / MCP23S17 SPI GPIO expander device services

-- Copyright (C)2017-2023, Philip Munts dba Munts Technologies.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are met:
--
-- * Redistributions of source code must retain the above copyright notice,
--   this list of conditions and the following disclaimer.
--
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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-- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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-- POSSIBILITY OF SUCH DAMAGE.

WITH GPIO;
WITH I2C;
WITH SPI;

PACKAGE MCP23x17 IS

  Error : EXCEPTION;

  TYPE DeviceClass IS TAGGED PRIVATE;

  TYPE Device IS ACCESS DeviceClass;

  SUBTYPE Address IS I2C.Address RANGE 16#20# .. 16#27#;

  DefaultAddress : CONSTANT Address := Address'First;

  -- MCP23017 I2C interface characteristics

  MaxSpeed : CONSTANT := I2C.SpeedFastPlus;

  -- MCP23S17 SPI interface characteristics

  SPI_Mode      : CONSTANT Natural := 0;
  SPI_WordSize  : CONSTANT Natural := 8;
  SPI_Frequency : CONSTANT Natural := 10_000_000;

  -- MCP23x17 hardware reset

  PROCEDURE Reset(Self : IN DeviceClass);

  -- MCP23017 I2C device initializer

  PROCEDURE Initialize
   (Self   : OUT DeviceClass;
    rstpin : NOT NULL GPIO.Pin;
    bus    : NOT NULL I2C.Bus;
    addr   : Address := DefaultAddress);

  -- MCP23017 I2C device object constructor

  FUNCTION Create
   (rstpin : NOT NULL GPIO.Pin;
    bus    : NOT NULL I2C.Bus;
    addr   : Address := DefaultAddress) RETURN Device;

  -- MCP23S17 SPI device initializer

  PROCEDURE Initialize
   (Self   : OUT DeviceClass;
    rstpin : NOT NULL GPIO.Pin;
    spidev : NOT NULL SPI.Device;
    addr   : Address := DefaultAddress);

  -- MCP23S17 SPI device object constructor

  FUNCTION Create
   (rstpin : NOT NULL GPIO.Pin;
    spidev : NOT NULL SPI.Device;
    addr   : Address := DefaultAddress) RETURN Device;

PRIVATE

  TYPE RegisterAddress8 IS MOD 2**8;
  TYPE RegisterAddress16 IS MOD 2**8;

  TYPE RegisterData8 IS MOD 2**8;
  TYPE RegisterData16 IS MOD 2**16;

  -- Define register address constants

  IODIRA   : CONSTANT RegisterAddress8 := 16#00#;
  IODIRB   : CONSTANT RegisterAddress8 := 16#01#;
  IPOLA    : CONSTANT RegisterAddress8 := 16#02#;
  IPOLB    : CONSTANT RegisterAddress8 := 16#03#;
  GPINTENA : CONSTANT RegisterAddress8 := 16#04#;
  GPINTENB : CONSTANT RegisterAddress8 := 16#05#;
  DEFVALA  : CONSTANT RegisterAddress8 := 16#06#;
  DEFVALB  : CONSTANT RegisterAddress8 := 16#07#;
  INTCONA  : CONSTANT RegisterAddress8 := 16#08#;
  INTCONB  : CONSTANT RegisterAddress8 := 16#09#;
  IOCONA   : CONSTANT RegisterAddress8 := 16#0A#;
  IOCONB   : CONSTANT RegisterAddress8 := 16#0B#;
  GPPUA    : CONSTANT RegisterAddress8 := 16#0C#;
  GPPUB    : CONSTANT RegisterAddress8 := 16#0D#;
  INTFA    : CONSTANT RegisterAddress8 := 16#0E#;
  INTFB    : CONSTANT RegisterAddress8 := 16#0F#;
  INTCAPA  : CONSTANT RegisterAddress8 := 16#10#;
  INTCAPB  : CONSTANT RegisterAddress8 := 16#11#;
  GPIOA    : CONSTANT RegisterAddress8 := 16#12#;
  GPIOB    : CONSTANT RegisterAddress8 := 16#13#;
  OLATA    : CONSTANT RegisterAddress8 := 16#14#;
  OLATB    : CONSTANT RegisterAddress8 := 16#15#;
  IOCON    : CONSTANT RegisterAddress8 := IOCONA;

  IODIR    : CONSTANT RegisterAddress16 := RegisterAddress16(IODIRA);
  IPOL     : CONSTANT RegisterAddress16 := RegisterAddress16(IPOLA);
  GPINTEN  : CONSTANT RegisterAddress16 := RegisterAddress16(GPINTENA);
  DEFVAL   : CONSTANT RegisterAddress16 := RegisterAddress16(DEFVALA);
  INTCON   : CONSTANT RegisterAddress16 := RegisterAddress16(INTCONA);
  GPPU     : CONSTANT RegisterAddress16 := RegisterAddress16(GPPUA);
  INTF     : CONSTANT RegisterAddress16 := RegisterAddress16(INTFA);
  INTCAP   : CONSTANT RegisterAddress16 := RegisterAddress16(INTCAPA);
  GPIODAT  : CONSTANT RegisterAddress16 := RegisterAddress16(GPIOA);
  GPIOLAT  : CONSTANT RegisterAddress16 := RegisterAddress16(OLATA);

  -- Read an 8-bit register

  PROCEDURE ReadRegister8
   (Self  : DeviceClass;
    reg   : RegisterAddress8;
    data  : OUT RegisterData8);

  -- Write an 8-bit register

  PROCEDURE WriteRegister8
   (Self  : DeviceClass;
    reg   : RegisterAddress8;
    data  : RegisterData8);

  -- Read a 16-bit register

  PROCEDURE ReadRegister16
   (Self  : DeviceClass;
    reg   : RegisterAddress16;
    data  : OUT RegisterData16);

  -- Write a 16-bit register pair

  PROCEDURE WriteRegister16
   (Self  : DeviceClass;
    reg   : RegisterAddress16;
    data  : RegisterData16);

  -- Complete the definition for MCP23x17.DeviceClass

  TYPE DeviceClass IS TAGGED RECORD
    rstpin : GPIO.Pin;
    i2cbus : I2C.Bus;     -- MCP23017 I2C
    spidev : SPI.Device;  -- MCP23S17 SPI
    addr   : Address;
  END RECORD;

END MCP23x17;