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#include "project.h"
#define GPIO_CLOCK GPIOA
#define GPIO_DATA GPIOB
#define CLOCK GPIO5
#define DATA GPIO11
#define KEYPAD_DELAY do { delay_us(1); } while (0)
#define SCAN_INTERVAL 73
#define DEBOUNCE_INTERVAL 1
#define DEBOUNCE_COUNT 3
static uint32_t next_scan;
uint16_t
keypad_raw_read (void)
{
uint16_t ret = 0;
uint16_t c;
/*Reset the state machine in the keypad */
gpio_set (GPIO_DATA, DATA);
KEYPAD_DELAY;
gpio_clear (GPIO_DATA, DATA);
KEYPAD_DELAY;
gpio_set (GPIO_DATA, DATA);
KEYPAD_DELAY;
gpio_clear (GPIO_CLOCK, CLOCK);
KEYPAD_DELAY;
for (c = 0x8000; c; c >>= 1)
{
gpio_set (GPIO_CLOCK, CLOCK);
KEYPAD_DELAY;
if (!(gpio_get (GPIO_DATA, DATA) & DATA))
ret |= c;
gpio_clear (GPIO_CLOCK, CLOCK);
KEYPAD_DELAY;
}
gpio_set (GPIO_CLOCK, CLOCK);
return ret;
}
uint16_t
keypad_read (void)
{
int c;
const uint8_t lut[] = "cdef89ab45670123";
uint8_t ret = 0;
/*Reset the state machine in the keypad */
gpio_set (GPIO_DATA, DATA);
KEYPAD_DELAY;
gpio_clear (GPIO_DATA, DATA);
KEYPAD_DELAY;
gpio_set (GPIO_DATA, DATA);
KEYPAD_DELAY;
gpio_clear (GPIO_CLOCK, CLOCK);
KEYPAD_DELAY;
for (c = 0; c < 16; ++c)
{
gpio_set (GPIO_CLOCK, CLOCK);
KEYPAD_DELAY;
if (!(gpio_get (GPIO_DATA, DATA) & DATA))
ret = lut[c];
gpio_clear (GPIO_CLOCK, CLOCK);
KEYPAD_DELAY;
}
gpio_set (GPIO_CLOCK, CLOCK);
return ret;
}
static void
keypad_scan (void)
{
static uint8_t last_v;
static uint8_t key_down;
static int same;
uint8_t v;
v = keypad_read ();
next_scan = DEBOUNCE_INTERVAL;
if (v!=last_v) {
last_v=v;
same=0;
return;
} else {
if (same<DEBOUNCE_COUNT) {
same++;
return;
}
}
if (!v && !key_down) {
next_scan = SCAN_INTERVAL;
return;
}
if (key_down==v) {
return;
} else if (key_down!=v) {
if (key_down)
key_event (key_down, 0);
key_down=v;
if (key_down)
key_event (key_down, 1);
}
}
void
keypad_tick (void)
{
if (!next_scan)
keypad_scan ();
else
next_scan--;
}
void
keypad_init (void)
{
gpio_set_mode (GPIO_CLOCK, GPIO_MODE_OUTPUT_50_MHZ,
GPIO_CNF_OUTPUT_OPENDRAIN, CLOCK);
gpio_set_mode (GPIO_DATA, GPIO_MODE_OUTPUT_50_MHZ,
GPIO_CNF_OUTPUT_OPENDRAIN, DATA);
}
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