- /* Copyright (C) 2014 by Jacob Alexander
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
- // ----- Includes -----
-
- // Compiler Includes
- #include <string.h> // For memcpy
-
- // Project Includes
- #include <Lib/OutputLib.h>
- #include <Lib/Interrupts.h>
-
- // Local Includes
- #include "uart_serial.h"
-
-
-
- // ----- Defines -----
-
- // UART Configuration
- #if defined(_mk20dx128_) || defined(_mk20dx128vlf5_) || defined(_mk20dx256_) // UART0 Debug
- #define UART_BDH UART0_BDH
- #define UART_BDL UART0_BDL
- #define UART_C1 UART0_C1
- #define UART_C2 UART0_C2
- #define UART_C3 UART0_C3
- #define UART_C4 UART0_C4
- #define UART_CFIFO UART0_CFIFO
- #define UART_D UART0_D
- #define UART_PFIFO UART0_PFIFO
- #define UART_RCFIFO UART0_RCFIFO
- #define UART_RWFIFO UART0_RWFIFO
- #define UART_S1 UART0_S1
- #define UART_S2 UART0_S2
- #define UART_SFIFO UART0_SFIFO
- #define UART_TWFIFO UART0_TWFIFO
-
- #define SIM_SCGC4_UART SIM_SCGC4_UART0
- #define IRQ_UART_STATUS IRQ_UART0_STATUS
-
- #elif defined(_mk20dx256vlh7_) // UART2 Debug
- #define UART_BDH UART2_BDH
- #define UART_BDL UART2_BDL
- #define UART_C1 UART2_C1
- #define UART_C2 UART2_C2
- #define UART_C3 UART2_C3
- #define UART_C4 UART2_C4
- #define UART_CFIFO UART2_CFIFO
- #define UART_D UART2_D
- #define UART_PFIFO UART2_PFIFO
- #define UART_RCFIFO UART2_RCFIFO
- #define UART_RWFIFO UART2_RWFIFO
- #define UART_S1 UART2_S1
- #define UART_S2 UART2_S2
- #define UART_SFIFO UART2_SFIFO
- #define UART_TWFIFO UART2_TWFIFO
-
- #define SIM_SCGC4_UART SIM_SCGC4_UART2
- #define IRQ_UART_STATUS IRQ_UART2_STATUS
-
- #endif
-
-
-
- // ----- Variables -----
-
- #define uart_buffer_size 128 // 128 byte buffer
- volatile uint8_t uart_buffer_head = 0;
- volatile uint8_t uart_buffer_tail = 0;
- volatile uint8_t uart_buffer_items = 0;
- volatile uint8_t uart_buffer[uart_buffer_size];
-
- volatile uint8_t uart_configured = 0;
-
-
-
- // ----- Interrupt Functions -----
-
- #if defined(_mk20dx128_) || defined(_mk20dx128vlf5_) || defined(_mk20dx256_) // UART0 Debug
- void uart0_status_isr()
- #elif defined(_mk20dx256vlh7_) // UART2 Debug
- void uart2_status_isr()
- #endif
- {
- cli(); // Disable Interrupts
-
- // UART0_S1 must be read for the interrupt to be cleared
- if ( UART_S1 & ( UART_S1_RDRF | UART_S1_IDLE ) )
- {
- uint8_t available = UART_RCFIFO;
-
- // If there was actually nothing
- if ( available == 0 )
- {
- // Cleanup
- available = UART_D;
- UART_CFIFO = UART_CFIFO_RXFLUSH;
- sei();
- return;
- }
-
- // Read UART0 into buffer until FIFO is empty
- while ( available-- > 0 )
- {
- uart_buffer[uart_buffer_tail++] = UART_D;
- uart_buffer_items++;
-
- // Wrap-around of tail pointer
- if ( uart_buffer_tail >= uart_buffer_size )
- {
- uart_buffer_tail = 0;
- }
-
- // Make sure the head pointer also moves if circular buffer is overwritten
- if ( uart_buffer_head == uart_buffer_tail )
- {
- uart_buffer_head++;
- }
-
- // Wrap-around of head pointer
- if ( uart_buffer_head >= uart_buffer_size )
- {
- uart_buffer_head = 0;
- }
- }
- }
-
- sei(); // Re-enable Interrupts
- }
-
-
-
- // ----- Functions -----
-
- void uart_serial_setup()
- {
- // Indication that the UART is not ready yet
- uart_configured = 0;
-
- // Setup the the UART interface for keyboard data input
- SIM_SCGC4 |= SIM_SCGC4_UART; // Disable clock gating
-
- // MCHCK / Kiibohd-dfu
- #if defined(_mk20dx128vlf5_)
- // Pin Setup for UART0
- PORTA_PCR1 = PORT_PCR_PE | PORT_PCR_PS | PORT_PCR_PFE | PORT_PCR_MUX(2); // RX Pin
- PORTA_PCR2 = PORT_PCR_DSE | PORT_PCR_SRE | PORT_PCR_MUX(2); // TX Pin
-
- // Kiibohd-dfu
- #elif defined(_mk20dx256vlh7_)
- // Pin Setup for UART2
- PORTD_PCR2 = PORT_PCR_PE | PORT_PCR_PS | PORT_PCR_PFE | PORT_PCR_MUX(3); // RX Pin
- PORTD_PCR3 = PORT_PCR_DSE | PORT_PCR_SRE | PORT_PCR_MUX(3); // TX Pin
-
- // Teensy
- #else
- // Pin Setup for UART0
- PORTB_PCR16 = PORT_PCR_PE | PORT_PCR_PS | PORT_PCR_PFE | PORT_PCR_MUX(3); // RX Pin
- PORTB_PCR17 = PORT_PCR_DSE | PORT_PCR_SRE | PORT_PCR_MUX(3); // TX Pin
- #endif
-
-
- #if defined(_mk20dx128_) || defined(_mk20dx128vlf5_) || defined(_mk20dx256_) // UART0 Debug
- // Setup baud rate - 115200 Baud
- // 48 MHz / ( 16 * Baud ) = BDH/L
- // Baud: 115200 -> 48 MHz / ( 16 * 115200 ) = 26.0416667
- // Thus baud setting = 26
- // NOTE: If finer baud adjustment is needed see UARTx_C4 -> BRFA in the datasheet
- uint16_t baud = 26; // Max setting of 8191
- UART_BDH = (uint8_t)(baud >> 8);
- UART_BDL = (uint8_t)baud;
- UART_C4 = 0x02;
-
- #elif defined(_mk20dx256vlh7_) // UART2 Debug
- // Setup baud rate - 115200 Baud
- // Uses Bus Clock
- // 24 MHz / ( 16 * Baud ) = BDH/L
- // Baud: 115200 -> 24 MHz / ( 16 * 115200 ) = 13.021
- // Thus baud setting = 13
- // NOTE: If finer baud adjustment is needed see UARTx_C4 -> BRFA in the datasheet
- uint16_t baud = 13; // Max setting of 8191
- UART_BDH = (uint8_t)(baud >> 8);
- UART_BDL = (uint8_t)baud;
- UART_C4 = 0x01;
-
- #endif
-
- // 8 bit, No Parity, Idle Character bit after stop
- UART_C1 = UART_C1_ILT;
-
- // Interrupt notification watermarks
- #if defined(_mk20dx128_) || defined(_mk20dx128vlf5_) || defined(_mk20dx256_) // UART0 Debug
- UART_TWFIFO = 2;
- UART_RWFIFO = 4;
- #elif defined(_mk20dx256vlh7_) // UART2 Debug
- // UART2 has a single byte FIFO
- UART_TWFIFO = 1;
- UART_RWFIFO = 1;
- #endif
-
- // TX FIFO Enabled, TX FIFO Size 1 (Max 8 datawords), RX FIFO Enabled, RX FIFO Size 1 (Max 8 datawords)
- // TX/RX FIFO Size:
- // 0x0 - 1 dataword
- // 0x1 - 4 dataword
- // 0x2 - 8 dataword
- UART_PFIFO = UART_PFIFO_TXFE | UART_PFIFO_RXFE;
-
- // Reciever Inversion Disabled, LSBF
- // UART_S2_RXINV UART_S2_MSBF
- UART_S2 |= 0x00;
-
- // Transmit Inversion Disabled
- // UART_C3_TXINV
- UART_C3 |= 0x00;
-
- // TX Enabled, RX Enabled, RX Interrupt Enabled, Generate idles
- // UART_C2_TE UART_C2_RE UART_C2_RIE UART_C2_ILIE
- UART_C2 = UART_C2_TE | UART_C2_RE | UART_C2_RIE | UART_C2_ILIE;
-
- // Add interrupt to the vector table
- NVIC_ENABLE_IRQ( IRQ_UART_STATUS );
-
- // UART is now ready to use
- uart_configured = 1;
- }
-
-
- // Get the next character, or -1 if nothing received
- int uart_serial_getchar()
- {
- if ( !uart_configured )
- return -1;
-
- unsigned int value = -1;
-
- // Check to see if the FIFO has characters
- if ( uart_buffer_items > 0 )
- {
- value = uart_buffer[uart_buffer_head++];
- uart_buffer_items--;
-
- // Wrap-around of head pointer
- if ( uart_buffer_head >= uart_buffer_size )
- {
- uart_buffer_head = 0;
- }
- }
-
- return value;
- }
-
-
- // Number of bytes available in the receive buffer
- int uart_serial_available()
- {
- return uart_buffer_items;
- }
-
-
- // Discard any buffered input
- void uart_serial_flush_input()
- {
- uart_buffer_head = 0;
- uart_buffer_tail = 0;
- uart_buffer_items = 0;
- }
-
-
- // Transmit a character. 0 returned on success, -1 on error
- int uart_serial_putchar( uint8_t c )
- {
- if ( !uart_configured )
- return -1;
-
- while ( !( UART_SFIFO & UART_SFIFO_TXEMPT ) ); // Wait till there is room to send
- UART_D = c;
-
- return 0;
- }
-
-
- int uart_serial_write( const void *buffer, uint32_t size )
- {
- if ( !uart_configured )
- return -1;
-
- const uint8_t *data = (const uint8_t *)buffer;
- uint32_t position = 0;
-
- // While buffer is not empty and transmit buffer is
- while ( position < size )
- {
- while ( !( UART_SFIFO & UART_SFIFO_TXEMPT ) ); // Wait till there is room to send
- UART_D = data[position++];
- }
-
- return 0;
- }
-
-
- void uart_serial_flush_output()
- {
- // Delay until buffer has been sent
- while ( !( UART_SFIFO & UART_SFIFO_TXEMPT ) ); // Wait till there is room to send
- }
-
-
- void uart_device_reload()
- {
- asm volatile("bkpt");
- }
-
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