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- /* Copyright (C) 2012 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 <Lib/ScanLib.h>
-
- // Project Includes
- #include <led.h>
- #include <print.h>
-
- // Local Includes
- #include "scan_loop.h"
-
-
-
- // ----- Defines -----
-
- // Pinout Defines
- #define REQUEST_PORT PORTD
- #define REQUEST_DDR DDRD
- #define REQUEST_PIN 3
- #define DATA_READ PIND
- #define DATA_PORT PORTD
- #define DATA_DDR DDRD
- #define DATA_PIN 2
-
- #define MAX_SAMPLES 10
- #define MAX_FAILURES 3731
- #define PACKET_STORAGE 24 // At worst only 8 packets, but with you keypresses you can get more
-
-
- // ----- Macros -----
-
- #define READ_DATA DATA_READ & (1 << DATA_PIN) ? 0 : 1
-
- #define REQUEST_DATA() REQUEST_DDR &= ~(1 << REQUEST_PIN) // Start incoming keyboard transfer
- #define STOP_DATA() REQUEST_DDR |= (1 << REQUEST_PIN) // Stop incoming keyboard data
-
- // Make sure we haven't overflowed the buffer
- #define bufferAdd(byte) \
- if ( KeyIndex_BufferUsed < KEYBOARD_BUFFER ) \
- KeyIndex_Buffer[KeyIndex_BufferUsed++] = byte
-
-
-
- // ----- Variables -----
-
- // Buffer used to inform the macro processing module which keys have been detected as pressed
- volatile uint8_t KeyIndex_Buffer[KEYBOARD_BUFFER];
- volatile uint8_t KeyIndex_BufferUsed;
-
-
-
- // ----- Function Declarations -----
-
- void processPacketValue( uint16_t packetValue );
-
-
-
- // ----- Interrupt Functions -----
-
- // XXX - None Required
-
-
-
- // ----- Functions -----
-
- // Setup
- // This setup is very simple, as there is no extra hardware used in this scan module, other than GPIOs.
- // To be nice, we wait a little bit after powering on, and dump any of the pending keyboard data.
- // Afterwards (as long as no keys were being held), the keyboard should have a clean buffer, and be ready to go.
- // (Even if keys were held down, everything should probably still work...)
- inline void scan_setup()
- {
- // Setup the DATA pin
- DATA_DDR &= ~(1 << DATA_PIN); // Set to input
- DATA_PORT |= (1 << DATA_PIN); // Set to pull-up resistor
-
- // Setup the REQUEST pin
- REQUEST_PORT |= (1 << REQUEST_PIN); // Set to output
- STOP_DATA(); // Set the line high to stop incoming data
- REQUEST_DATA();
-
- DDRD |= (1 << 4);
- PORTD &= ~(1 << 4);
-
- // Message
- info_print("Pins Setup");
-
- // Reset the keyboard before scanning, we might be in a wierd state
- _delay_ms( 50 );
- //scan_resetKeyboard();
-
- // Message
- info_print("Keyboard Buffer Flushed");
- }
-
-
- // Main Detection Loop
- // The Univac-Sperry F3W9 has a convenient feature, an internal 8 key buffer
- // This buffer is only emptied (i.e. sent over the bus) when the REQUEST line is held high
- // Because of this, we can utilize the scan_loop to do all of the critical processing,
- // without having to resort to interrupts, giving the data reading 100% of the CPU.
- // This is because the USB interrupts can wait until the scan_loop is finished to continue.
- //
- // Normally, this approach isn't taken, as it's easier/faster/safer to use Teensy hardware shift registers
- // for serial data transfers.
- // However, since the Univac-Sperry F3W9 sends 20 bit packets (including the start bit), the Teensy
- // doesn't have a shift register large enough (9 bit max), to hold the data.
- // So the line must be polled manually using CPU cycles
- //
- // Another interesting feature is that there are 2 data lines.
- // Output and /Output (NOT'ted version).
- // Not really useful here, but could be used for error checking, or eliminating an external NOT gate if
- // we were using (but can't...) a hardware decoder like a USART.
- inline uint8_t scan_loop()
- {
- return 0;
- // Protocol Notes:
- // - Packets are 20 bits long, including the start bit
- // - Each bit is ~105 usecs in length
- // - Thus the average packet length is 2.205 msecs
- // - Each packet is separated by at least 240 usecs (during a buffer unload)
- // - While holding the key down, each packet has a space of about 910 usecs
- // - A max of 8 keys can be sent at once (note, the arrow keys seem use 2 packets each, and thus take up twice as much buffer)
- // - There is no timing danger for holding the request line, just that data may come in when you don't want it
-
- // Now that the scan loop has been entered, we don't have to worry about interrupts stealing
- // precious cycles.
- REQUEST_DATA();
-
- // = Delays =
- //
- // For these calculations to work out properly, then Teensy should be running at 16 MHz
- // - 1 bit : 105 usecs is 16 000 000 * 0.000105 = 1680 instructions
- // - Bit centering : 52.5 usecs is 16 000 000 * 0.0000525 = 840 instructions
- // - Delay : 5 msecs is 16 000 000 * 0.005 = 80 000 instructions
- // - Microsecond : 1 usec is 16 000 000 * 0.000001 = 16 instructions
- //
- // Now, either I can follow these exactly, or based upon the fact that I have >840 tries to find the
- // the start bit, and >1680 tries to read the subsequent bits, I have some "flex" time.
- // Knowing this, I can make some assumptions that because I'm only reading a total of 20 bits, and will
- // be re-centering for each packet.
- // This will allow for less worrying about compiler optimizations (and porting!).
-
- // The basic idea is to find a "reliable" value for the start bit, e.g. read it ~10 times.
- // Using a for-loop and some addition counters, this should eat up approximately 20-30 instructions per read
- // (very loose estimation).
- // So reading 10 * 30 instructions = 300 instructions, which is much less than 840 instructions to where the
- // bit center is, but is close enough that further delays of ~>1680 instructions will put the next read
- // within the next bit period.
- // This is all possible because interrupts are disabled at this point, otherwise, all of this reasoning
- // would fall apart.
- // _delay_us is available to use, fortunately.
-
- // Input Packet Storage (before being processed)
- uint16_t incomingPacket[PACKET_STORAGE];
- uint8_t numberOfIncomingPackets = 0;
-
- // Sample the data line for ~5 ms, looking for a start bit
- // - Sampling every 1 usecs, looking for 10 good samples
- // - Accumulated samples will dumped if a high is detected
- uint8_t samples = 0;
- uint16_t failures = 0;
-
- // Continue waiting for a start bit until MAX_FAILURES has been reached (~5ms of nothing)
- while ( failures <= MAX_FAILURES )
- {
- // Attempt to find the start bit
- while ( samples < MAX_SAMPLES )
- {
- // Delay first
- _delay_us( 1 );
-
- // If data is valid, increment
- if ( READ_DATA )
- {
- samples++;
- }
- // Reset
- else
- {
- samples = 0;
- failures++;
-
- // After ~5ms of failures, break the loop
- // Each failure is approx 5 instructions + 1 usec, or approximately 1.34 usec)
- // So ~3731 failures for ~5ms
- // Being exact doesn't matter, as this is just to let the other parts of the
- // controller do some processing
- if ( failures > MAX_FAILURES )
- break;
- }
- }
-
- // If 10 valid samples of the start bit were obtained,
- if ( samples >= MAX_SAMPLES )
- {
- // Clean out the old packet memory
- incomingPacket[numberOfIncomingPackets] = 0;
-
- // Read the next 19 bits into memory (bit 0 is the start bit, which is always 0)
- for ( uint8_t c = 1; c < 20; c++ )
- {
- // Wait until the middle of the next bit
- _delay_us( 105 );
-
- // Append the current bit value
- incomingPacket[numberOfIncomingPackets] |= (READ_DATA << c);
- }
-
- // Packet finished, increment counter
- numberOfIncomingPackets++;
- }
- }
-
- // Stop the keyboard input
- STOP_DATA();
-
- // Finished receiving data from keyboard, start packet processing
- for ( uint8_t packet = 0; packet < numberOfIncomingPackets; packet++ )
- processPacketValue( incomingPacket[packet] );
-
- return 0;
- }
-
- // Read in the Packet Data, and decide what to do with it
- void processPacketValue( uint16_t packetValue )
- {
- // = Packet Layout =
- //
- // A is the first bit received (bit 0), T is the last
- //
- // | Modifier? | ?? | Scan Code |
- // A B C D E F G H I J K L M N O P Q R S T
- //
- // A - Start bit
- // - Always Low
- // B -> H - Modifier enabled bits
- // - Each bit represents a different modifier "mode"
- // - B -> Shift/Lock
- // - C -> ??
- // - D -> Func
- // - E -> ??
- // - F -> ??
- // - G -> ??
- // - H -> ??
- // I -> L - ?? No idea yet...
- // - The bits change for some combinations, but not pattern has been found yet...
- // - I -> ??
- // - J -> ??
- // - K -> ??
- // - L -> ??
- // M -> T - Scan Code
- // - Bits are organized from low to high (8 bit value)
- // - M -> Bit 1
- // - N -> Bit 2
- // - O -> Bit 3
- // - P -> Bit 4
- // - Q -> Bit 5
- // - R -> Bit 6
- // - S -> Bit 7
- // - T -> Bit 8
-
- // Separate packet into sections
- uint8_t scanCode = (packetValue & 0xFF000) << 12;
- uint8_t modifiers = (packetValue & 0x000FE);
- uint8_t extra = (packetValue & 0x00F00) << 8;
-
- // Debug Info
- char tmpStr1[3];
- char tmpStr2[3];
- char tmpStr3[3];
- hexToStr_op( scanCode, tmpStr1, 2 );
- hexToStr_op( modifiers, tmpStr2, 2 );
- hexToStr_op( extra, tmpStr3, 2 );
- dbug_dPrint( "Scancode: 0x", tmpStr1, " Modifiers: 0x", tmpStr2, " Extra: 0x", tmpStr3 );
- dbug_dPrint( "Packet: 0x", tmpStr2, tmpStr3, tmpStr1 );
-
- // TODO List
- // - Modifier keys
- // - Key Release mechanism
-
- // Compute Modifier keys
- // TODO
-
- // Deal with special scan codes
- switch ( scanCode )
- {
- default:
- //bufferAdd( scanCode ); TODO - Uncomment when ready for USB output
- break;
- }
- }
-
- // Send data
- // NOTE: Does nothing with the Univac-Sperry F3W9
- uint8_t scan_sendData( uint8_t dataPayload )
- {
- return 0;
- }
-
- // Signal KeyIndex_Buffer that it has been properly read
- inline void scan_finishedWithBuffer( uint8_t sentKeys )
- {
- return;
- }
-
- // Signal that the keys have been properly sent over USB
- // TODO
- inline void scan_finishedWithUSBBuffer( uint8_t sentKeys )
- {
- /*
- uint8_t foundModifiers = 0;
-
- // Look for all of the modifiers present, there is a max of 8 (but only keys for 5 on the HASCI version)
- for ( uint8_t c = 0; c < KeyIndex_BufferUsed; c++ )
- {
- // The modifier range is from 0x80 to 0x8F (well, the last bit is the ON/OFF signal, but whatever...)
- if ( KeyIndex_Buffer[c] <= 0x8F && KeyIndex_Buffer[c] >= 0x80 )
- {
- // Add the modifier back into the the Key Buffer
- KeyIndex_Buffer[foundModifiers] = KeyIndex_Buffer[c];
- foundModifiers++;
- }
- }
-
- // Adjust the size of the new Key Buffer
- KeyIndex_BufferUsed = foundModifiers;
- */
- }
-
- // Reset/Hold keyboard
- // NOTE: Does nothing with the Univac-Sperry F3W9
- void scan_lockKeyboard( void )
- {
- }
-
- // NOTE: Does nothing with the Univac-Sperry F3W9
- void scan_unlockKeyboard( void )
- {
- }
-
- // Reset Keyboard
- // - Holds the input read line high to flush the buffer
- // - This does not actually reset the keyboard, but always seems brings it to a sane state
- // - Won't work fully if keys are being pressed done at the same time
- void scan_resetKeyboard( void )
- {
- // Initiate data request line, but don't read the incoming data
- REQUEST_DATA();
-
- // We shouldn't be receiving more than 8 packets (and maybe +1 error signal)
- // This is around 22 ms of data, so a delay of 50 ms should be sufficient.
- _delay_ms( 50 );
-
- // Stop request line
- STOP_DATA();
- }
-
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