/* 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 #include #include 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_send1[SIZE_BUF_SEND]; static volatile uint8_t buf_send2[SIZE_BUF_SEND]; static volatile uint8_t *buf_send_sys, *buf_send_user; static volatile int8_t send_switch; static volatile int8_t update; #if 0 #define TWI_DEBUG(x) rs232_putc (x) #else #define TWI_DEBUG(x) #endif void twi_init (uint8_t addr) { send_switch = 0; update = 0; buf_send_sys = buf_send1; buf_send_user = buf_send2; TWAR = addr; TWSR = 0x00; TWCR = _BV(TWEA) | _BV(TWEN) | _BV(TWIE); } SIGNAL (SIG_2WIRE_SERIAL) { TWI_DEBUG (';'); switch (TW_STATUS) { /* slave transmitter mode */ /* START + SLA|W + ACK */ case TW_ST_SLA_ACK: case TW_ST_ARB_LOST_SLA_ACK: TWI_DEBUG ('a'); if (send_switch && !update) { volatile uint8_t *tmp = buf_send_sys; buf_send_sys = buf_send_user; buf_send_user = tmp; send_switch = 0; } send_idx = 0; /* no break */ case TW_ST_DATA_ACK: TWI_DEBUG ('b'); TWDR = buf_send_sys[send_idx++]; if (SIZE_BUF_SEND == send_idx) TWCR &= ~_BV(TWEA); break; case TW_ST_DATA_NACK: case TW_ST_LAST_DATA: TWI_DEBUG ('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: TWI_DEBUG ('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: TWI_DEBUG ('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: TWI_DEBUG ('x'); buf_rcpt[twi_rcpt_tail++] = TWDR; /* no break */ /* STOP */ case TW_SR_STOP: TWI_DEBUG ('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) { update = 1; send_switch = 1; while (size --) buf_send_user[size] = buf[size]; update = 0; }