--- /dev/null
+/* 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.
+ */
+
+#include "uart_serial.h"
+#include <Lib/OutputLib.h>
+#include <Lib/Interrupts.h>
+#include <string.h> // For memcpy
+
+// ----- Variables -----
+
+#define uart0_buffer_size 32 // 32 byte buffer
+volatile uint8_t uart0_buffer_head = 0;
+volatile uint8_t uart0_buffer_tail = 0;
+volatile uint8_t uart0_buffer_items = 0;
+volatile uint8_t uart0_buffer[uart0_buffer_size];
+
+
+// ----- Interrupt Functions -----
+
+void uart0_status_isr()
+{
+ cli(); // Disable Interrupts
+
+ // UART0_S1 must be read for the interrupt to be cleared
+ if ( UART0_S1 & UART_S1_RDRF )
+ {
+ // Read UART0 into buffer until FIFO is empty
+ while ( !( UART0_SFIFO & UART_SFIFO_RXEMPT ) )
+ {
+ uart0_buffer[uart0_buffer_tail++] = UART0_D;
+ uart0_buffer_items++;
+
+ // Wrap-around of tail pointer
+ if ( uart0_buffer_tail >= uart0_buffer_size )
+ {
+ uart0_buffer_tail = 0;
+ }
+
+ // Make sure the head pointer also moves if circular buffer is overwritten
+ if ( uart0_buffer_head == uart0_buffer_tail )
+ {
+ uart0_buffer_head++;
+ }
+
+ // Wrap-around of head pointer
+ if ( uart0_buffer_head >= uart0_buffer_size )
+ {
+ uart0_buffer_head = 0;
+ }
+
+ }
+ }
+
+ sei(); // Re-enable Interrupts
+}
+
+
+// ----- Functions -----
+
+void uart_serial_setup()
+{
+ // Setup the the UART interface for keyboard data input
+ SIM_SCGC4 |= SIM_SCGC4_UART0; // Disable clock gating
+
+ // 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
+
+ // Setup baud rate - 9600 Baud
+ // 48 MHz / ( 16 * Baud ) = BDH/L
+ // Baud: 9600 -> 48 MHz / ( 16 * 9600 ) = 312.5
+ // Thus baud setting = 313
+ // NOTE: If finer baud adjustment is needed see UARTx_C4 -> BRFA in the datasheet
+ uint16_t baud = 313; // Max setting of 8191
+ UART0_BDH = (uint8_t)(baud >> 8);
+ UART0_BDL = (uint8_t)baud;
+
+ // 8 bit, No Parity, Idle Character bit after stop
+ UART0_C1 = UART_C1_ILT;
+
+ // TX FIFO Disabled, 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
+ UART0_PFIFO = UART_PFIFO_TXFE | UART_PFIFO_RXFE;
+
+ // Reciever Inversion Disabled, LSBF
+ // UART_S2_RXINV UART_S2_MSBF
+ UART0_S2 |= 0x00;
+
+ // Transmit Inversion Disabled
+ // UART_C3_TXINV
+ UART0_C3 |= 0x00;
+
+ // TX Disabled, RX Enabled, RX Interrupt Enabled
+ // UART_C2_TE UART_C2_RE UART_C2_RIE
+ UART0_C2 = UART_C2_TE | UART_C2_RE | UART_C2_RIE;
+
+ // Add interrupt to the vector table
+ NVIC_ENABLE_IRQ( IRQ_UART0_STATUS );
+}
+
+
+// Get the next character, or -1 if nothing received
+int uart_serial_getchar()
+{
+ unsigned int value = -1;
+
+ // Check to see if the FIFO has characters
+ if ( uart0_buffer_items > 0 )
+ {
+ value = uart0_buffer[uart0_buffer_head++];
+ uart0_buffer_items--;
+
+ // Wrap-around of head pointer
+ if ( uart0_buffer_head >= uart0_buffer_size )
+ {
+ uart0_buffer_head = 0;
+ }
+ }
+
+ return value;
+}
+
+
+// Number of bytes available in the receive buffer
+int uart_serial_available()
+{
+ return uart0_buffer_items;
+}
+
+
+// Discard any buffered input
+void uart_serial_flush_input()
+{
+ uart0_buffer_head = 0;
+ uart0_buffer_tail = 0;
+ uart0_buffer_items = 0;
+}
+
+
+// Transmit a character. 0 returned on success, -1 on error
+int uart_serial_putchar( uint8_t c )
+{
+ return uart_serial_write( &c, 1 );
+}
+
+
+int uart_serial_write( const void *buffer, uint32_t size )
+{
+ 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 ( !( UART0_SFIFO & UART_SFIFO_TXEMPT ) ); // Wait till there is room to send
+ UART0_D = data[position++];
+ }
+
+ return 0;
+}
+
+
+void uart_serial_flush_output()
+{
+ // Delay until buffer has been sent
+ while ( !( UART0_SFIFO & UART_SFIFO_TXEMPT ) ); // Wait till there is room to send
+}
+
+
+void uart_device_reload()
+{
+ asm volatile("bkpt");
+}
+
projects / kiibohd-controller.git / blobdiff