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authordemonchy2005-03-29 18:26:54 +0000
committerdemonchy2005-03-29 18:26:54 +0000
commitc602781645a70d01b104225bde9d7491e27700c8 (patch)
tree6861566a30a4fa0c2a6dc3701c74d8b01a2d01fc /n/avr/twi-slave/twi_slave.c
parent6d40a5d17f21ecac61d8b41e030cac2560b87511 (diff)
Initial revision
Diffstat (limited to 'n/avr/twi-slave/twi_slave.c')
-rw-r--r--n/avr/twi-slave/twi_slave.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/n/avr/twi-slave/twi_slave.c b/n/avr/twi-slave/twi_slave.c
new file mode 100644
index 0000000..9746120
--- /dev/null
+++ b/n/avr/twi-slave/twi_slave.c
@@ -0,0 +1,130 @@
+/* twi.c */
+/* n.avr.twi - AVR TWI Module. {{{
+ *
+ * Copyright (C) 2004 Clément Demonchy
+ *
+ * Robot APB Team/Efrei 2005.
+ * Web: http://assos.efrei.fr/robot/
+ * Email: robot AT efrei DOT fr
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * }}} */
+#include "twi_slave.h"
+#include "n/avr/rs232/rs232.h"
+
+#include <avr/io.h>
+#include <avr/twi.h>
+#include <avr/signal.h>
+
+//TODO acces exclusif au buffer
+
+static volatile uint8_t twi_rcpt_tail;
+static volatile uint8_t send_idx;
+static volatile uint8_t data_ready;
+static volatile uint8_t buf_rcpt[SIZE_BUF_RCPT];
+static volatile uint8_t buf_send[SIZE_BUF_SEND];
+
+void
+twi_init (uint8_t addr)
+{
+ TWAR = addr;
+ TWSR = 0x00;
+ TWCR = _BV(TWEA) | _BV(TWEN) | _BV(TWIE);
+}
+
+
+SIGNAL (SIG_2WIRE_SERIAL)
+{
+ rs232_putc (';');
+ switch (TW_STATUS)
+ {
+ /* slave transmitter mode */
+ /* START + SLA|W + ACK */
+ case TW_ST_SLA_ACK:
+ case TW_ST_ARB_LOST_SLA_ACK:
+ rs232_putc ('a');
+ send_idx = 0;
+ /* no break */
+ case TW_ST_DATA_ACK:
+ rs232_putc ('b');
+ TWDR = buf_send[send_idx++];
+ if (SIZE_BUF_SEND - send_idx == 1)
+ TWCR &= ~_BV(TWEA);
+ break;
+ case TW_ST_DATA_NACK:
+ case TW_ST_LAST_DATA:
+ rs232_putc ('c');
+ TWCR |= _BV (TWEA);
+ break;
+ /* slave receiver mode */
+ /* START + SLA|W + ACK */
+ case TW_SR_SLA_ACK:
+ case TW_SR_ARB_LOST_SLA_ACK:
+ case TW_SR_GCALL_ACK:
+ case TW_SR_ARB_LOST_GCALL_ACK:
+ rs232_putc ('z');
+ data_ready = 0;
+ twi_rcpt_tail = 0;
+ if (SIZE_BUF_RCPT == 1)
+ TWCR &= ~_BV(TWEA);
+ break;
+ /* DATA + ACK */
+ case TW_SR_DATA_ACK:
+ case TW_SR_GCALL_DATA_ACK:
+ rs232_putc ('y');
+ buf_rcpt[twi_rcpt_tail++] = TWDR;
+ if (SIZE_BUF_RCPT - twi_rcpt_tail == 1)
+ TWCR &= ~_BV(TWEA);
+ break;
+ /* DATA + NACK */
+ case TW_SR_DATA_NACK:
+ case TW_SR_GCALL_DATA_NACK:
+ rs232_putc ('x');
+ buf_rcpt[twi_rcpt_tail++] = TWDR;
+ /* no break */
+ /* STOP */
+ case TW_SR_STOP:
+ rs232_putc ('w');
+ data_ready = 1;
+ break;
+ }
+ TWCR |= _BV(TWINT);
+}
+
+/** Recopie dans les données recues dans buf.
+ */
+uint8_t
+twi_poll (uint8_t buf[], uint8_t size)
+{
+ if (data_ready)
+ {
+ data_ready = 0;
+ while (size --)
+ buf[size] = buf_rcpt[size];
+ TWCR |= _BV (TWEA);
+ return 1;
+ }
+ else
+ return 0;
+}
+
+void
+twi_update (uint8_t buf[], uint8_t size)
+{
+ while (size --)
+ buf_send[size] = buf[size];
+}
+