5 Right now just handle "write" to the serial port at any speed
6 and printf to the console when '\n' is written.
8 Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
10 This file is part of simavr.
12 simavr is free software: you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation, either version 3 of the License, or
15 (at your option) any later version.
17 simavr is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
22 You should have received a copy of the GNU General Public License
23 along with simavr. If not, see <http://www.gnu.org/licenses/>.
30 #define FONT_GREEN "\e[32m"
31 #define FONT_DEFAULT "\e[0m"
40 //#define TRACE(_w) _w
45 DEFINE_FIFO(uint8_t, uart_fifo);
47 static avr_cycle_count_t avr_uart_txc_raise(struct avr_t * avr, avr_cycle_count_t when, void * param)
49 avr_uart_t * p = (avr_uart_t *)param;
50 if (avr_regbit_get(avr, p->txen)) {
51 // if the interrupts are not used, still raise the UDRE and TXC flag
52 avr_raise_interrupt(avr, &p->udrc);
53 avr_raise_interrupt(avr, &p->txc);
58 static avr_cycle_count_t avr_uart_rxc_raise(struct avr_t * avr, avr_cycle_count_t when, void * param)
60 avr_uart_t * p = (avr_uart_t *)param;
61 if (avr_regbit_get(avr, p->rxen))
62 avr_raise_interrupt(avr, &p->rxc);
66 static uint8_t avr_uart_rxc_read(struct avr_t * avr, avr_io_addr_t addr, void * param)
68 avr_uart_t * p = (avr_uart_t *)param;
69 uint8_t v = avr_core_watch_read(avr, addr);
71 //static uint8_t old = 0xff; if (v != old) printf("UCSRA read %02x\n", v); old = v;
73 // if RX is enabled, and there is nothing to read, and
74 // the AVR core is reading this register, it's probably
75 // to poll the RXC TXC flag and spinloop
76 // so here we introduce a usleep to make it a bit lighter
77 // on CPU and let data arrive
79 uint8_t ri = !avr_regbit_get(avr, p->rxen) || !avr_regbit_get(avr, p->rxc.raised);
80 uint8_t ti = !avr_regbit_get(avr, p->txen) || !avr_regbit_get(avr, p->txc.raised);
82 if (p->flags & AVR_UART_FLAG_POOL_SLEEP) {
87 // if reception is idle and the fifo is empty, tell whomever there is room
88 if (avr_regbit_get(avr, p->rxen) && uart_fifo_isempty(&p->input)) {
89 avr_raise_irq(p->io.irq + UART_IRQ_OUT_XOFF, 0);
90 avr_raise_irq(p->io.irq + UART_IRQ_OUT_XON, 1);
96 static uint8_t avr_uart_read(struct avr_t * avr, avr_io_addr_t addr, void * param)
98 avr_uart_t * p = (avr_uart_t *)param;
100 // clear the rxc bit in case the code is using polling
101 avr_regbit_clear(avr, p->rxc.raised);
103 if (!avr_regbit_get(avr, p->rxen)) {
105 // made to trigger potential watchpoints
106 avr_core_watch_read(avr, addr);
109 uint8_t v = uart_fifo_read(&p->input);
111 // TRACE(printf("UART read %02x %s\n", v, uart_fifo_isempty(&p->input) ? "EMPTY!" : "");)
113 // made to trigger potential watchpoints
114 v = avr_core_watch_read(avr, addr);
116 // trigger timer if more characters are pending
117 if (!uart_fifo_isempty(&p->input))
118 avr_cycle_timer_register_usec(avr, p->usec_per_byte, avr_uart_rxc_raise, p);
123 static void avr_uart_baud_write(struct avr_t * avr, avr_io_addr_t addr, uint8_t v, void * param)
125 avr_uart_t * p = (avr_uart_t *)param;
126 avr_core_watch_write(avr, addr, v);
127 uint32_t val = avr->data[p->r_ubrrl] | (avr->data[p->r_ubrrh] << 8);
128 uint32_t baud = avr->frequency / (val+1);
129 if (avr_regbit_get(avr, p->u2x))
134 const int databits[] = { 5,6,7,8, /* 'reserved', assume 8 */8,8,8, 9 };
135 int db = databits[avr_regbit_get(avr, p->ucsz) | (avr_regbit_get(avr, p->ucsz2) << 2)];
136 int sb = 1 + avr_regbit_get(avr, p->usbs);
137 int word_size = 1 /* start */ + db /* data bits */ + 1 /* parity */ + sb /* stops */;
139 printf("UART-%c configured to %04x = %d bps (x%d), %d data %d stop\n",
140 p->name, val, baud, avr_regbit_get(avr, p->u2x)?2:1, db, sb);
141 // TODO: Use the divider value and calculate the straight number of cycles
142 p->usec_per_byte = 1000000 / (baud / word_size);
143 printf("Roughtly %d usec per bytes\n", (int)p->usec_per_byte);
146 static void avr_uart_write(struct avr_t * avr, avr_io_addr_t addr, uint8_t v, void * param)
148 avr_uart_t * p = (avr_uart_t *)param;
150 if (addr == p->r_udr) {
151 avr_core_watch_write(avr, addr, v);
154 avr_regbit_clear(avr, p->udrc.raised);
155 avr_cycle_timer_register_usec(avr,
156 p->usec_per_byte, avr_uart_txc_raise, p); // should be uart speed dependent
158 if (p->flags & AVR_UART_FLAG_STDIO) {
159 static char buf[128];
161 buf[l++] = v < ' ' ? '.' : v;
163 if (v == '\n' || l == 127) {
165 printf( FONT_GREEN "%s\n" FONT_DEFAULT, buf);
168 TRACE(printf("UDR%c(%02x) = %02x\n", p->name, addr, v);)
169 // tell other modules we are "outputing" a byte
170 if (avr_regbit_get(avr, p->txen))
171 avr_raise_irq(p->io.irq + UART_IRQ_OUTPUT, v);
173 if (p->udrc.vector && addr == p->udrc.enable.reg) {
175 * If enabling the UDRC interrupt, raise it immediately if FIFO is empty
177 uint8_t udrce = avr_regbit_get(avr, p->udrc.enable);
178 avr_core_watch_write(avr, addr, v);
179 uint8_t nudrce = avr_regbit_get(avr, p->udrc.enable);
180 if (!udrce && nudrce) {
181 // if the FIDO is not empty (clear timer is flying) we don't
182 // need to raise the interrupt, it will happen when the timer
184 if (avr_cycle_timer_status(avr, avr_uart_txc_raise, p) == 0)
185 avr_raise_interrupt(avr, &p->udrc);
188 if (p->udrc.vector && addr == p->udrc.raised.reg) {
189 // get the bits before the write
190 //uint8_t udre = avr_regbit_get(avr, p->udrc.raised);
191 uint8_t txc = avr_regbit_get(avr, p->txc.raised);
193 // no need to write this value in here, only the
194 // interrupt flags need clearing!
195 // avr_core_watch_write(avr, addr, v);
197 //avr_clear_interrupt_if(avr, &p->udrc, udre);
198 avr_clear_interrupt_if(avr, &p->txc, txc);
202 static void avr_uart_irq_input(struct avr_irq_t * irq, uint32_t value, void * param)
204 avr_uart_t * p = (avr_uart_t *)param;
205 avr_t * avr = p->io.avr;
207 // check to see fi receiver is enabled
208 if (!avr_regbit_get(avr, p->rxen))
211 if (uart_fifo_isempty(&p->input))
212 avr_cycle_timer_register_usec(avr, p->usec_per_byte, avr_uart_rxc_raise, p); // should be uart speed dependent
213 uart_fifo_write(&p->input, value); // add to fifo
215 TRACE(printf("UART IRQ in %02x (%d/%d) %s\n", value, p->input.read, p->input.write, uart_fifo_isfull(&p->input) ? "FULL!!" : "");)
217 if (uart_fifo_isfull(&p->input))
218 avr_raise_irq(p->io.irq + UART_IRQ_OUT_XOFF, 1);
222 void avr_uart_reset(struct avr_io_t *io)
224 avr_uart_t * p = (avr_uart_t *)io;
225 avr_t * avr = p->io.avr;
227 avr_regbit_set(avr, p->udrc.raised);
228 avr_irq_register_notify(p->io.irq + UART_IRQ_INPUT, avr_uart_irq_input, p);
229 avr_cycle_timer_cancel(avr, avr_uart_rxc_raise, p);
230 avr_cycle_timer_cancel(avr, avr_uart_txc_raise, p);
231 uart_fifo_reset(&p->input);
233 // DEBUG allow printf without fidding with enabling the uart
234 avr_regbit_set(avr, p->txen);
235 p->usec_per_byte = 100;
238 static int avr_uart_ioctl(struct avr_io_t * port, uint32_t ctl, void * io_param)
240 avr_uart_t * p = (avr_uart_t *)port;
246 if (ctl == AVR_IOCTL_UART_SET_FLAGS(p->name)) {
247 p->flags = *(uint32_t*)io_param;
250 if (ctl == AVR_IOCTL_UART_GET_FLAGS(p->name)) {
251 *(uint32_t*)io_param = p->flags;
258 static const char * irq_names[UART_IRQ_COUNT] = {
259 [UART_IRQ_INPUT] = "8<in",
260 [UART_IRQ_OUTPUT] = "8>out",
261 [UART_IRQ_OUT_XON] = ">xon",
262 [UART_IRQ_OUT_XOFF] = ">xoff",
265 static avr_io_t _io = {
267 .reset = avr_uart_reset,
268 .ioctl = avr_uart_ioctl,
269 .irq_names = irq_names,
272 void avr_uart_init(avr_t * avr, avr_uart_t * p)
276 // printf("%s UART%c UDR=%02x\n", __FUNCTION__, p->name, p->r_udr);
278 p->flags = AVR_UART_FLAG_POOL_SLEEP|AVR_UART_FLAG_STDIO;
280 avr_register_io(avr, &p->io);
281 avr_register_vector(avr, &p->rxc);
282 avr_register_vector(avr, &p->txc);
283 avr_register_vector(avr, &p->udrc);
285 // allocate this module's IRQ
286 avr_io_setirqs(&p->io, AVR_IOCTL_UART_GETIRQ(p->name), UART_IRQ_COUNT, NULL);
287 // Only call callbacks when the value change...
288 p->io.irq[UART_IRQ_OUT_XOFF].flags |= IRQ_FLAG_FILTERED;
290 avr_register_io_write(avr, p->r_udr, avr_uart_write, p);
291 avr_register_io_read(avr, p->r_udr, avr_uart_read, p);
292 // monitor code that reads the rxc flag, and delay it a bit
293 avr_register_io_read(avr, p->rxc.raised.reg, avr_uart_rxc_read, p);
296 avr_register_io_write(avr, p->udrc.enable.reg, avr_uart_write, p);
298 avr_register_io_write(avr, p->r_ucsra, avr_uart_write, p);
300 avr_register_io_write(avr, p->r_ubrrl, avr_uart_baud_write, p);