4 Handles the 8 bits and 16 bits AVR timer.
9 Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
11 This file is part of simavr.
13 simavr is free software: you can redistribute it and/or modify
14 it under the terms of the GNU General Public License as published by
15 the Free Software Foundation, either version 3 of the License, or
16 (at your option) any later version.
18 simavr is distributed in the hope that it will be useful,
19 but WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 GNU General Public License for more details.
23 You should have received a copy of the GNU General Public License
24 along with simavr. If not, see <http://www.gnu.org/licenses/>.
28 #include "avr_timer.h"
29 #include "avr_ioport.h"
32 * The timers are /always/ 16 bits here, if the higher byte register
33 * is specified it's just added.
35 static uint16_t _timer_get_ocr(avr_timer_t * p, int compi)
37 return p->io.avr->data[p->comp[compi].r_ocr] |
38 (p->comp[compi].r_ocrh ? (p->io.avr->data[p->comp[compi].r_ocrh] << 8) : 0);
40 static uint16_t _timer_get_tcnt(avr_timer_t * p)
42 return p->io.avr->data[p->r_tcnt] |
43 (p->r_tcnth ? (p->io.avr->data[p->r_tcnth] << 8) : 0);
45 static uint16_t _timer_get_icr(avr_timer_t * p)
47 return p->io.avr->data[p->r_icr] |
48 (p->r_tcnth ? (p->io.avr->data[p->r_icrh] << 8) : 0);
50 static avr_cycle_count_t avr_timer_comp(avr_timer_t *p, avr_cycle_count_t when, uint8_t comp)
52 avr_t * avr = p->io.avr;
53 avr_raise_interrupt(avr, &p->comp[comp].interrupt);
55 // check output compare mode and set/clear pins
56 uint8_t mode = avr_regbit_get_array(avr, p->comp[comp].com,
57 ARRAY_SIZE(p->comp[comp].com));
58 avr_irq_t * irq = &p->io.irq[TIMER_IRQ_OUT_COMP + comp];
61 case avr_timer_com_normal: // Normal mode OCnA disconnected
63 case avr_timer_com_toggle: // Toggle OCnA on compare match
64 if (p->comp[comp].com_pin.reg) // we got a physical pin
66 0x100 + (avr_regbit_get(avr, p->comp[comp].com_pin) ? 0 : 1));
67 else // no pin, toggle the IRQ anyway
69 p->io.irq[TIMER_IRQ_OUT_COMP + comp].value ? 0 : 1);
71 case avr_timer_com_clear:
72 avr_raise_irq(irq, 0);
74 case avr_timer_com_set:
75 avr_raise_irq(irq, 1);
79 return p->tov_cycles ? 0 : p->comp[comp].comp_cycles ? when
80 + p->comp[comp].comp_cycles : 0;
83 static avr_cycle_count_t avr_timer_compa(struct avr_t * avr, avr_cycle_count_t when, void * param)
85 return avr_timer_comp((avr_timer_t*)param, when, AVR_TIMER_COMPA);
88 static avr_cycle_count_t avr_timer_compb(struct avr_t * avr, avr_cycle_count_t when, void * param)
90 return avr_timer_comp((avr_timer_t*)param, when, AVR_TIMER_COMPB);
93 static avr_cycle_count_t avr_timer_compc(struct avr_t * avr, avr_cycle_count_t when, void * param)
95 return avr_timer_comp((avr_timer_t*)param, when, AVR_TIMER_COMPC);
98 static avr_cycle_count_t avr_timer_tov(struct avr_t * avr, avr_cycle_count_t when, void * param)
100 avr_timer_t * p = (avr_timer_t *)param;
101 int start = p->tov_base == 0;
104 avr_raise_interrupt(avr, &p->overflow);
107 static const avr_cycle_timer_t dispatch[AVR_TIMER_COMP_COUNT] =
108 { avr_timer_compa, avr_timer_compb, avr_timer_compc };
110 for (int compi = 0; compi < AVR_TIMER_COMP_COUNT; compi++) {
111 if (p->comp[compi].comp_cycles) {
112 if (p->comp[compi].comp_cycles < p->tov_cycles)
113 avr_cycle_timer_register(avr,
114 p->comp[compi].comp_cycles - (avr->cycle - p->tov_base),
116 else if (p->tov_cycles == p->comp[compi].comp_cycles && !start)
117 dispatch[compi](avr, when, param);
121 return when + p->tov_cycles;
125 static uint8_t avr_timer_tcnt_read(struct avr_t * avr, avr_io_addr_t addr, void * param)
127 avr_timer_t * p = (avr_timer_t *)param;
128 // made to trigger potential watchpoints
131 uint64_t when = avr->cycle - p->tov_base;
133 uint16_t tcnt = (when * p->tov_top) / p->tov_cycles;
134 // printf("%s-%c when = %d tcnt = %d/%d\n", __FUNCTION__, p->name, (uint32_t)when, tcnt, p->tov_top);
136 avr->data[p->r_tcnt] = tcnt;
138 avr->data[p->r_tcnth] = tcnt >> 8;
141 return avr_core_watch_read(avr, addr);
144 static void avr_timer_tcnt_write(struct avr_t * avr, avr_io_addr_t addr, uint8_t v, void * param)
146 avr_timer_t * p = (avr_timer_t *)param;
147 avr_core_watch_write(avr, addr, v);
148 uint16_t tcnt = _timer_get_tcnt(p);
153 if (tcnt >= p->tov_top)
156 // this involves some magicking
157 // cancel the current timers, recalculate the "base" we should be at, reset the
158 // timer base as it should, and re-shedule the timers using that base.
160 avr_cycle_timer_cancel(avr, avr_timer_tov, p);
161 avr_cycle_timer_cancel(avr, avr_timer_compa, p);
162 avr_cycle_timer_cancel(avr, avr_timer_compb, p);
163 avr_cycle_timer_cancel(avr, avr_timer_compc, p);
165 uint64_t cycles = (tcnt * p->tov_cycles) / p->tov_top;
167 // printf("%s-%c %d/%d -- cycles %d/%d\n", __FUNCTION__, p->name, tcnt, p->tov_top, (uint32_t)cycles, (uint32_t)p->tov_cycles);
169 // this reset the timers bases to the new base
171 avr_cycle_timer_register(avr, p->tov_cycles - cycles, avr_timer_tov, p);
172 avr_timer_tov(avr, avr->cycle - cycles, p);
174 // tcnt = ((avr->cycle - p->tov_base) * p->tov_top) / p->tov_cycles;
175 // printf("%s-%c new tnt derive to %d\n", __FUNCTION__, p->name, tcnt);
178 static void avr_timer_configure(avr_timer_t * p, uint32_t clock, uint32_t top)
180 float t = clock / (float)(top+1);
181 float frequency = p->io.avr->frequency;
186 p->tov_cycles = frequency / t; // avr_hz_to_cycles(frequency, t);
187 printf("%s-%c TOP %.2fHz = %d cycles\n", __FUNCTION__, p->name, t, (int)p->tov_cycles);
189 for (int compi = 0; compi < AVR_TIMER_COMP_COUNT; compi++) {
190 uint32_t ocr = _timer_get_ocr(p, compi);
191 float fc = clock / (float)(ocr);
193 p->comp[compi].comp_cycles = 0;
194 // printf("%s-%c clock %d top %d OCR%c %d\n", __FUNCTION__, p->name, clock, top, 'A'+compi, ocr);
196 if (ocr && ocr <= top) {
197 p->comp[compi].comp_cycles = frequency / fc; // avr_hz_to_cycles(p->io.avr, fa);
198 printf("%s-%c %c %.2fHz = %d cycles\n", __FUNCTION__, p->name,
199 'A'+compi, fc, (int)p->comp[compi].comp_cycles);
203 if (p->tov_cycles > 1) {
204 avr_cycle_timer_register(p->io.avr, p->tov_cycles, avr_timer_tov, p);
205 // calling it once, with when == 0 tells it to arm the A/B/C timers if needed
207 avr_timer_tov(p->io.avr, p->io.avr->cycle, p);
211 static void avr_timer_reconfigure(avr_timer_t * p)
213 avr_t * avr = p->io.avr;
215 avr_timer_wgm_t zero={0};
218 p->comp[AVR_TIMER_COMPA].comp_cycles = 0;
219 p->comp[AVR_TIMER_COMPB].comp_cycles = 0;
220 p->comp[AVR_TIMER_COMPC].comp_cycles = 0;
223 avr_cycle_timer_cancel(avr, avr_timer_tov, p);
224 avr_cycle_timer_cancel(avr, avr_timer_compa, p);
225 avr_cycle_timer_cancel(avr, avr_timer_compb, p);
226 avr_cycle_timer_cancel(avr, avr_timer_compc, p);
228 long clock = avr->frequency;
230 // only can exists on "asynchronous" 8 bits timers
231 if (avr_regbit_get(avr, p->as2))
234 uint8_t cs = avr_regbit_get_array(avr, p->cs, ARRAY_SIZE(p->cs));
236 printf("%s-%c clock turned off\n", __FUNCTION__, p->name);
240 uint8_t mode = avr_regbit_get_array(avr, p->wgm, ARRAY_SIZE(p->wgm));
241 uint8_t cs_div = p->cs_div[cs];
242 uint32_t f = clock >> cs_div;
244 p->mode = p->wgm_op[mode];
245 //printf("%s-%c clock %d, div %d(/%d) = %d ; mode %d\n", __FUNCTION__, p->name, clock, cs, 1 << cs_div, f, mode);
246 switch (p->mode.kind) {
247 case avr_timer_wgm_normal:
248 avr_timer_configure(p, f, (1 << p->mode.size) - 1);
250 case avr_timer_wgm_ctc: {
251 avr_timer_configure(p, f, _timer_get_ocr(p, AVR_TIMER_COMPA));
253 case avr_timer_wgm_pwm: {
254 uint16_t top = p->mode.top == avr_timer_wgm_reg_ocra ? _timer_get_ocr(p, AVR_TIMER_COMPA) : _timer_get_icr(p);
255 avr_timer_configure(p, f, top);
257 case avr_timer_wgm_fast_pwm:
258 // avr_timer_configure(p, f, (1 << p->mode.size) - 1);
261 printf("%s-%c unsupported timer mode wgm=%d (%d)\n", __FUNCTION__, p->name, mode, p->mode.kind);
265 static void avr_timer_write_ocr(struct avr_t * avr, avr_io_addr_t addr, uint8_t v, void * param)
267 avr_timer_t * p = (avr_timer_t *)param;
268 avr_core_watch_write(avr, addr, v);
270 switch (p->mode.kind) {
271 case avr_timer_wgm_pwm:
272 if (p->mode.top != avr_timer_wgm_reg_ocra) {
273 avr_raise_irq(p->io.irq + TIMER_IRQ_OUT_PWM0, _timer_get_ocr(p, AVR_TIMER_COMPA));
274 avr_raise_irq(p->io.irq + TIMER_IRQ_OUT_PWM1, _timer_get_ocr(p, AVR_TIMER_COMPB));
277 case avr_timer_wgm_fast_pwm:
278 avr_raise_irq(p->io.irq + TIMER_IRQ_OUT_PWM0, _timer_get_ocr(p, AVR_TIMER_COMPA));
279 avr_raise_irq(p->io.irq + TIMER_IRQ_OUT_PWM1, _timer_get_ocr(p, AVR_TIMER_COMPB));
282 printf("%s-%c mode %d\n", __FUNCTION__, p->name, p->mode.kind);
283 avr_timer_reconfigure(p);
288 static void avr_timer_write(struct avr_t * avr, avr_io_addr_t addr, uint8_t v, void * param)
290 avr_timer_t * p = (avr_timer_t *)param;
291 avr_core_watch_write(avr, addr, v);
292 avr_timer_reconfigure(p);
295 static void avr_timer_reset(avr_io_t * port)
297 avr_timer_t * p = (avr_timer_t *)port;
298 avr_cycle_timer_cancel(p->io.avr, avr_timer_tov, p);
299 avr_cycle_timer_cancel(p->io.avr, avr_timer_compa, p);
300 avr_cycle_timer_cancel(p->io.avr, avr_timer_compb, p);
301 avr_cycle_timer_cancel(p->io.avr, avr_timer_compc, p);
303 // check to see if the comparators have a pin output. If they do,
304 // (try) to get the ioport corresponding IRQ and connect them
305 // they will automagically be triggered when the comparator raises
307 for (int compi = 0; compi < AVR_TIMER_COMP_COUNT; compi++) {
308 p->comp[compi].comp_cycles = 0;
310 avr_ioport_getirq_t req = {
311 .bit = p->comp[compi].com_pin
313 if (avr_ioctl(port->avr, AVR_IOCTL_IOPORT_GETIRQ_REGBIT, &req) > 0) {
315 // printf("%s-%c COMP%c Connecting PIN IRQ %d\n", __FUNCTION__, p->name, 'A'+compi, req.irq[0]->irq);
316 avr_connect_irq(&port->irq[TIMER_IRQ_OUT_COMP + compi], req.irq[0]);
321 static avr_io_t _io = {
323 .reset = avr_timer_reset,
326 void avr_timer_init(avr_t * avr, avr_timer_t * p)
330 // allocate this module's IRQ
331 p->io.irq_count = TIMER_IRQ_COUNT;
332 p->io.irq = avr_alloc_irq(0, p->io.irq_count);
333 p->io.irq_ioctl_get = AVR_IOCTL_TIMER_GETIRQ(p->name);
334 p->io.irq[TIMER_IRQ_OUT_PWM0].flags |= IRQ_FLAG_FILTERED;
335 p->io.irq[TIMER_IRQ_OUT_PWM1].flags |= IRQ_FLAG_FILTERED;
337 avr_register_io(avr, &p->io);
338 avr_register_vector(avr, &p->overflow);
339 avr_register_vector(avr, &p->icr);
341 avr_register_io_write(avr, p->cs[0].reg, avr_timer_write, p);
344 * Even if the timer is 16 bits, we don't care to have watches on the
345 * high bytes because the datasheet says that the low address is always
348 for (int compi = 0; compi < AVR_TIMER_COMP_COUNT; compi++) {
349 avr_register_vector(avr, &p->comp[compi].interrupt);
351 if (p->comp[compi].r_ocr) // not all timers have all comparators
352 avr_register_io_write(avr, p->comp[compi].r_ocr, avr_timer_write_ocr, p);
354 avr_register_io_write(avr, p->r_tcnt, avr_timer_tcnt_write, p);
355 avr_register_io_read(avr, p->r_tcnt, avr_timer_tcnt_read, p);