Revision 10
Update timer.c
| lab2/i8254.h | ||
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| 35 | 35 |
#define TIMER_LSB BIT(4) /**< @brief Initialize Counter LSB only */ |
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#define TIMER_MSB BIT(5) /**< @brief Initialize Counter MSB only */ |
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#define TIMER_LSB_MSB (TIMER_LSB | TIMER_MSB) /**< @brief Initialize LSB first and MSB afterwards */ |
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#define TIMER_INMODE_MASK 0x30 |
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#define TIMER_INMODE_MASK 0x30 //0011 0000
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#define TIMER_INMODE_POS 4 |
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/* Operating mode: bits 3, 2 and 1 */ |
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#define TIMER_SQR_WAVE (BIT(2) | BIT(1)) /**< @brief Mode 3: square wave generator */ |
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#define TIMER_RATE_GEN BIT(2) /**< @brief Mode 2: rate generator */ |
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#define TIMER_MODE_MASK 0x0e /**< @brief Mask for mode */
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#define TIMER_MODE_MASK 0x0E /**< @brief Mask for mode */
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#define TIMER_MODE_POS 1 /**< @brief Position of smallest bit from mode */ |
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/* Counting mode: bit 0 */ |
| lab2/timer.c | ||
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| 6 | 6 |
#include "i8254.h" |
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int (timer_set_frequency)(uint8_t timer, uint32_t freq) {
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/* To be implemented by the students */ |
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printf("%s is not yet implemented!\n", __func__);
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// counter_init = clock/feq |
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uint8_t status = 0; |
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if (timer_get_conf(timer, &status)) return 1; |
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//Make command |
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uint8_t write_cmd = 0; |
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//Select timer |
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switch(timer) {
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case 0: write_cmd |= TIMER_SEL0; |
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break; |
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case 1: write_cmd |= TIMER_SEL1; |
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break; |
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case 2: write_cmd |= TIMER_SEL2; |
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break; |
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default: return 1; break; |
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} |
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//Change both LSB and MSB |
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write_cmd |= TIMER_LSB_MSB; |
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//Keep 4 least significant bits |
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write_cmd |= (status & (TIMER_MODE_MASK | TIMER_BCD)); |
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//Write cmd |
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sys_outb(TIMER_CTRL, ) |
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return 1; |
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} |
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|
| ... | ... | |
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int (timer_get_conf)(uint8_t timer, uint8_t *st) {
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// Write read-back command to TIMER_CTRL |
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int write_port = TIMER_CTRL; |
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u32_t cmd = TIMER_RB_CMD | TIMER_RB_COUNT_ | TIMER_RB_SEL(timer); |
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if(sys_outb(write_port, cmd)) return 1;
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if(sys_outb(TIMER_CTRL, cmd)) return 1;
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| 39 | 61 |
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int read_port; |
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switch(timer) {
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