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155 | --
-- Author: Brent Seidel
-- Date: 9-Aug-2024
--
-- This file is part of bbs_embed.
-- Bbs_embed is free software: you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the
-- Free Software Foundation, either version 3 of the License, or (at your
-- option) any later version.
--
-- bbs_embed is distributed in the hope that it will be useful, but
-- WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-- Public License for more details.
--
-- You should have received a copy of the GNU General Public License along
-- with bbs_embed. If not, see <https://www.gnu.org/licenses/>.--
--
with SAM3x8e.UART;
with SAM3x8e;
use type SAM3x8e.Bit;
use type SAM3x8e.Byte;
use type SAM3x8e.UInt32;
with BBS.embed.due.dev;
with BBS.embed.GPIO.Due;
with Ada.Interrupts;
with Ada.Interrupts.Names;
--
-- This package is the root of the serial I/O functionality on the Arduino
-- Due. It has four of its serial ports wired to the headers. These ports
-- are numbered 0 through 3. Port 0 is also wired to the programming USB
-- connector and is used as the default port, if none is specified.
--
-- Communications is available in both polled and interrupt driven varients.
-- Polled is unbuffered and has very little memory overhead, but puts more
-- load on the CPU. It is most useful when memory is tight or serial I/O
-- needs are minimal. It would also be useful as a method of last resort
-- for printing messages from an exception handler.
--
-- Interrupt driven copies messages into a buffer and uses an interrupt
-- handler to feed characters into the UART as needed. The main thread of
-- software can continue processing while this is happening. This provides
-- more processing for user software at the expense of requiring memory for
-- the buffers.
--
-- This package contains definitions and code that is common to both methods.
-- The interrupt or polled specific definitions and code are in the
-- appropriate sub-package.
--
package BBS.embed.due.serial is
--
-- The Arduino has four serial ports wired to the headers.
--
type port_id is new Integer range 0 .. 3;
--
-- The programming USB port is connected to pins PA08 and PA09 - URXD and
-- UTXD. These are controlled by the UART. Include code here to
-- initialize the UART and set the baud rate.
--
procedure init(baud_rate : SAM3x8e.UInt32);
procedure init(chan_num : port_id; baud_rate : SAM3x8e.UInt32);
--
-- Check if the transmitter is ready
--
function tx_ready return Boolean;
function tx_ready(chan : port_id) return Boolean;
--
-- Check if the receiver is ready
--
function rx_ready return Boolean;
function rx_ready(chan : port_id) return Boolean;
--
-- Check if the transmitter is empty.
--
function tx_empty return Boolean;
function tx_empty(chan : port_id) return Boolean;
private
--
-- Constants for some special characters.
--
BS : constant Character := Character'Val(8);
LF : constant Character := Character'Val(10);
CR : constant Character := Character'Val(13);
DEL : constant Character := Character'Val(127);
Serial : aliased SAM3x8e.UART.UART_Peripheral
with Import, Address => SAM3x8e.UART_Base;
--
-- The USARTs seem to be a superset of the UART, so the following works,
-- but leaves the more advanced features of the USARTs unavailable.
--
Serial0 : aliased SAM3x8e.UART.UART_Peripheral
with Import, Address => SAM3x8e.USART0_Base;
-- Universal Synchronous Asynchronous Receiver Transmitter 1
Serial1 : aliased SAM3x8e.UART.UART_Peripheral
with Import, Address => SAM3x8e.USART1_Base;
-- Universal Synchronous Asynchronous Receiver Transmitter 2
-- This does not seem to be available on the Arduino Due pin headers.
Serial2 : aliased SAM3x8e.UART.UART_Peripheral
with Import, Address => SAM3x8e.USART2_Base;
-- Universal Synchronous Asynchronous Receiver Transmitter 3
Serial3 : aliased SAM3x8e.UART.UART_Peripheral
with Import, Address => SAM3x8e.USART3_Base;
--
-- Create a serial channel information record. This should contain all
-- the information necessary to identify a serial port and the pins used
-- by it.
--
type serial_access is access all SAM3x8e.UART.UART_Peripheral;
type channel_info_rec is tagged limited record
dev_id : SAM3x8e.Byte; -- UART device ID
port : serial_access; -- Access to UART registers
pioc : BBS.embed.GPIO.Due.pio_access; -- PIO controlling pins
tx_pin : SAM3x8e.Byte; -- Transmit pin on PIO
rx_pin : SAM3x8e.Byte; -- Receive pin on PIO
tx_absel : SAM3x8e.Bit; -- A/B selection on PIO for transmit
rx_absel : SAM3x8e.Bit; -- A/B selection on PIO for receive
int_id : Ada.Interrupts.Interrupt_ID; -- Interrupt for channel
end record;
type serial_obj is access constant channel_info_rec;
--
-- May need a serial channel for the USB port - TODO
--
--
-- The Arduino Due has four serial channels wired to the headers.
-- 0 - UART
-- 1 - USART0
-- 2 - USART1
-- 3 - USART3
--
chan0 : aliased constant channel_info_rec := (dev_id => dev.UART_ID, port => Serial'Access,
pioc => BBS.embed.GPIO.Due.PIOA'Access, tx_pin => 9,
rx_pin => 8, tx_absel => 0, rx_absel => 0,
int_id => Ada.Interrupts.Names.UART_Interrupt);
chan1 : aliased constant channel_info_rec := (dev_id => dev.USART0_ID, port => Serial0'Access,
pioc => BBS.embed.GPIO.Due.PIOA'Access, tx_pin => 11,
rx_pin => 10, tx_absel => 0, rx_absel => 0,
int_id => Ada.Interrupts.Names.USART0_Interrupt);
chan2 : aliased constant channel_info_rec := (dev_id => dev.USART1_ID, port => Serial1'Access,
pioc => BBS.embed.GPIO.Due.PIOA'Access, tx_pin => 13,
rx_pin => 12, tx_absel => 0, rx_absel => 0,
int_id => Ada.Interrupts.Names.USART1_Interrupt);
chan3 : aliased constant channel_info_rec := (dev_id => dev.USART3_ID, port => Serial3'Access,
pioc => BBS.embed.GPIO.Due.PIOD'Access, tx_pin => 4,
rx_pin => 5, tx_absel => 1, rx_absel => 1,
int_id => Ada.Interrupts.Names.USART3_Interrupt);
channel : constant array (port_id'Range) of serial_obj := (chan0'Access, chan1'Access,
chan2'Access, chan3'Access);
end BBS.embed.due.serial;
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