1 /* Copyright (C) 2011 by Jacob Alexander
3 * Permission is hereby granted, free of charge, to any person obtaining a copy
4 * of this software and associated documentation files (the "Software"), to deal
5 * in the Software without restriction, including without limitation the rights
6 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7 * copies of the Software, and to permit persons to whom the Software is
8 * furnished to do so, subject to the following conditions:
10 * The above copyright notice and this permission notice shall be included in
11 * all copies or substantial portions of the Software.
13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 // ----- Includes -----
26 #include <avr/pgmspace.h>
27 #include <avr/interrupt.h>
30 //#include "usb_keys.h"
31 #include "scan_loop.h"
32 //#include "layouts.h"
33 //#include "usb_keyboard.h"
35 #include "usb_keyboard_debug.h"
41 // ----- Defines -----
43 // Verified Keypress Defines
44 #define USB_TRANSFER_DIVIDER 10 // 1024 == 1 Send of keypresses per second, 1 == 1 Send of keypresses per ~1 millisecond
49 #define CPU_PRESCALE(n) (CLKPR = 0x80, CLKPR = (n))
53 // ----- Variables -----
55 // Timer Interrupt for flagging a send of the sampled key detection data to the USB host
56 uint16_t sendKeypressCounter = 0;
58 // Flag generated by the timer interrupt
59 volatile uint8_t sendKeypresses = 0;
63 // ----- Functions -----
65 // Initial Pin Setup, make sure they are sane
66 inline void pinSetup(void)
68 // For each pin, 0=input, 1=output
77 // Setting pins to either high or pull-up resistor
88 // Setup with 16 MHz clock
97 // Setup ISR Timer for flagging a kepress send to USB
98 // Set to 256 * 1024 (8 bit timer with Clock/1024 prescalar) timer
101 TIMSK0 = (1 << TOIE0);
103 // Main Detection Loop
107 // Loop should never get here (indicate error)
110 // HID Debug Error message
111 erro_print("Detection loop error, this is very bad...bug report!");
113 // Send keypresses over USB if the ISR has signalled that it's time
114 if ( !sendKeypresses )
120 // Clear sendKeypresses Flag
125 ISR( TIMER0_OVF_vect )
127 sendKeypressCounter++;
128 if ( sendKeypressCounter > USB_TRANSFER_DIVIDER ) {
129 sendKeypressCounter = 0;