Merge commit 'a074364c37' as 'tmk_core'

tmk_core/protocol/ibm4704.c

@@ -0,0 +1,169 @@
+/*
+Copyright 2010,2011,2012,2013 Jun WAKO <wakojun@gmail.com>
+*/
+#include <stdbool.h>
+#include <util/delay.h>
+#include "debug.h"
+#include "ibm4704.h"
+
+
+#define WAIT(stat, us, err) do { \
+    if (!wait_##stat(us)) { \
+        ibm4704_error = err; \
+        goto ERROR; \
+    } \
+} while (0)
+
+
+uint8_t ibm4704_error = 0;
+
+
+void ibm4704_init(void)
+{
+    inhibit();
+}
+
+/*
+Host to Keyboard
+----------------
+Data bits are LSB first and Parity is odd. Clock has around 60us high and 30us low part.
+
+        ____        __   __   __   __   __   __   __   __   __   ________
+Clock       \______/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/
+            ^   ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ___
+Data    ____|__/    X____X____X____X____X____X____X____X____X____X   \___
+            |  Start   0    1    2    3    4    5    6    7    P   Stop
+            Request by host
+
+Start bit:  can be long as 300-350us.
+Request:    Host pulls Clock line down to request to send a command.
+Timing:     After Request keyboard pull up Data and down Clock line to low for start bit.
+            After request host release Clock line once Data line becomes hi.
+            Host writes a bit while Clock is hi and Keyboard reads while low.
+Stop bit:   Host releases or pulls up Data line to hi after 9th clock and waits for keyboard pull down the line to lo.
+*/
+uint8_t ibm4704_send(uint8_t data)
+{
+    bool parity = true; // odd parity
+    ibm4704_error = 0;
+
+    /* Request to send */
+    idle();
+    clock_lo();
+
+    /* wait for Start bit(Clock:lo/Data:hi) */
+    WAIT(data_hi, 300, 0x30);
+
+    /* Data bit */
+    for (uint8_t i = 0; i < 8; i++) {
+        WAIT(clock_hi, 100, 0x40+i);
+        //_delay_us(5);
+        if (data&(1<<i)) {
+            parity = !parity;
+            data_hi();
+        } else {
+            data_lo();
+        }
+        WAIT(clock_lo, 100, 0x48+i);
+    }
+
+    /* Parity bit */
+    WAIT(clock_hi, 100, 0x34);
+    if (parity) { data_hi(); } else { data_lo(); }
+    WAIT(clock_lo, 100, 0x35);
+
+    /* Stop bit */
+    WAIT(clock_hi, 100, 0x34);
+    data_hi();
+
+    /* End */
+    WAIT(data_lo, 100, 0x36);
+
+    inhibit();
+    _delay_us(200); // wait to recover clock to hi
+    return 0;
+ERROR:
+    inhibit();
+    if (ibm4704_error >= 0x30) {
+        xprintf("x%02X ", ibm4704_error);
+    }
+    _delay_us(200); // wait to recover clock to hi
+    return -1;
+}
+
+/* receive data when host want else inhibit communication */
+uint8_t ibm4704_recv_response(void)
+{
+    // 250 * 100us(wait start bit in ibm4704_recv)
+    uint8_t data = 0;
+    uint8_t try = 250;
+    do {
+        data = ibm4704_recv();
+    } while (try-- && ibm4704_error);
+    return data;
+}
+
+/*
+Keyboard to Host
+----------------
+Data bits are LSB first and Parity is odd. Clock has around 60us high and 30us low part.
+
+        ____      __   __   __   __   __   __   __   __   __   ________
+Clock       \____/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/
+             ____ ____ ____ ____ ____ ____ ____ ____ ____ ____    
+Data    ____/    X____X____X____X____X____X____X____X____X____X________
+            Start   0    1    2    3    4    5    6    7    P  Stop
+
+Start bit:  can be long as 300-350us.
+Inhibit:    Pull Data line down to inhibit keyboard to send.
+Timing:     Host reads bit while Clock is hi.
+Stop bit:   Keyboard pulls down Data line to lo after 9th clock.
+*/
+uint8_t ibm4704_recv(void)
+{
+    uint8_t data = 0;
+    bool parity = true;    // odd parity
+    ibm4704_error = IBM4704_ERR_NONE;
+
+    idle();
+    _delay_us(5);   // wait for line settles
+
+    /* start bit */
+    WAIT(clock_lo, 100, 0x11); // wait for keyboard to send
+    WAIT(data_hi, 100, 0x12);  // can be delayed that long
+
+    WAIT(clock_hi, 100, 0x13); // first rising edge which can take longer
+    /* data */
+    for (uint8_t i = 0; i < 8; i++) {
+        WAIT(clock_hi, 100, 0x20+i);
+        //_delay_us(5);
+        if (data_in()) {
+            parity = !parity;
+            data |= (1<<i);
+        }
+        WAIT(clock_lo, 150, 0x28+i);
+    }
+
+    /* parity */
+    WAIT(clock_hi, 100, 0x17);
+    if (data_in() != parity) {
+        ibm4704_error = IBM4704_ERR_PARITY;
+        goto ERROR;
+    }
+    WAIT(clock_lo, 150, 0x18);
+
+    /* stop bit */
+    WAIT(clock_hi, 100, 0x19);
+    WAIT(data_lo, 1, 0x19);
+
+    inhibit();
+    _delay_us(200); // wait to recover clock to hi
+    return data;
+ERROR:
+    if (ibm4704_error > 0x12) {
+        xprintf("x%02X ", ibm4704_error);
+    }
+    inhibit();
+    _delay_us(200); // wait to recover clock to hi
+    return -1;
+}