1 /*This file is prepared for Doxygen automatic documentation generation.*/
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2 /*! \file *********************************************************************
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4 * \brief USART driver for AVR32 UC3.
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6 * This file contains basic functions for the AVR32 USART, with support for all
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7 * modes, settings and clock speeds.
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9 * - Compiler: IAR EWAVR32 and GNU GCC for AVR32
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10 * - Supported devices: All AVR32 devices with a USART module can be used.
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13 * \author Atmel Corporation: http://www.atmel.com \n
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14 * Support and FAQ: http://support.atmel.no/
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16 ******************************************************************************/
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18 /* Copyright (c) 2007, Atmel Corporation All rights reserved.
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20 * Redistribution and use in source and binary forms, with or without
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21 * modification, are permitted provided that the following conditions are met:
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23 * 1. Redistributions of source code must retain the above copyright notice,
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24 * this list of conditions and the following disclaimer.
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26 * 2. Redistributions in binary form must reproduce the above copyright notice,
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27 * this list of conditions and the following disclaimer in the documentation
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28 * and/or other materials provided with the distribution.
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30 * 3. The name of ATMEL may not be used to endorse or promote products derived
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31 * from this software without specific prior written permission.
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33 * THIS SOFTWARE IS PROVIDED BY ATMEL ``AS IS'' AND ANY EXPRESS OR IMPLIED
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34 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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35 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND
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36 * SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT,
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37 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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38 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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39 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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40 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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49 //------------------------------------------------------------------------------
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50 /*! \name Private Functions
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55 /*! \brief Checks if the USART is in multidrop mode.
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57 * \param usart Base address of the USART instance.
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59 * \return \c 1 if the USART is in multidrop mode, otherwise \c 0.
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62 __attribute__((__always_inline__))
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64 static __inline__ int usart_mode_is_multidrop(volatile avr32_usart_t *usart)
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66 return ((usart->mr >> AVR32_USART_MR_PAR_OFFSET) & AVR32_USART_MR_PAR_MULTI) == AVR32_USART_MR_PAR_MULTI;
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70 /*! \brief Calculates a clock divider (\e CD) that gets the USART as close to a
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71 * wanted baudrate as possible.
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73 * \todo manage the FP fractal part to avoid big errors
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75 * Baudrate calculation:
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76 * \f$ baudrate = \frac{Selected Clock}{16 \times CD} \f$ with 16x oversampling or
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77 * \f$ baudrate = \frac{Selected Clock}{8 \times CD} \f$ with 8x oversampling or
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78 * \f$ baudrate = \frac{Selected Clock}{CD} \f$ with SYNC bit set to allow high speed.
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80 * \param usart Base address of the USART instance.
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81 * \param baudrate Wanted baudrate.
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82 * \param pba_hz USART module input clock frequency (PBA clock, Hz).
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84 * \retval USART_SUCCESS Baudrate successfully initialized.
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85 * \retval USART_INVALID_INPUT Wanted baudrate is impossible with given clock speed.
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88 static int usart_set_baudrate(volatile avr32_usart_t *usart, unsigned int baudrate, long pba_hz)
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93 // Baudrate calculation.
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94 if (baudrate < pba_hz / 16)
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96 // Use 16x oversampling, clear SYNC bit.
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97 usart->mr &=~ (AVR32_USART_MR_OVER_MASK | AVR32_USART_MR_SYNC_MASK);
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98 cd = (pba_hz + 8 * baudrate) / (16 * baudrate);
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100 if ((cd >65535)) return USART_INVALID_INPUT;
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102 else if (baudrate < pba_hz / 8)
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104 // Use 8x oversampling.
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105 usart->mr |= AVR32_USART_MR_OVER_MASK;
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107 usart->mr &=~ AVR32_USART_MR_SYNC_MASK;
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109 cd = (pba_hz + 4 * baudrate) / (8 * baudrate);
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111 if ((cd < 1)||(cd >65535)) return USART_INVALID_INPUT;
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116 usart->mr |= AVR32_USART_MR_SYNC_MASK;
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117 // use PBA/BaudRate
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118 cd = (pba_hz / baudrate);
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120 usart->brgr = cd << AVR32_USART_BRGR_CD_OFFSET;
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122 return USART_SUCCESS;
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128 //------------------------------------------------------------------------------
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129 /*! \name Initialization Functions
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134 void usart_reset(volatile avr32_usart_t *usart)
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136 // Disable all USART interrupts.
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137 // Interrupts needed should be set explicitly on every reset.
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138 usart->idr = 0xFFFFFFFF;
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140 // Reset mode and other registers that could cause unpredictable behavior after reset.
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145 // Shutdown TX and RX (will be re-enabled when setup has successfully completed),
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146 // reset status bits and turn off DTR and RTS.
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147 usart->cr = AVR32_USART_CR_RSTRX_MASK |
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148 AVR32_USART_CR_RSTTX_MASK |
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149 AVR32_USART_CR_RSTSTA_MASK |
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150 AVR32_USART_CR_RSTIT_MASK |
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151 AVR32_USART_CR_RSTNACK_MASK |
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152 AVR32_USART_CR_DTRDIS_MASK |
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153 AVR32_USART_CR_RTSDIS_MASK;
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157 int usart_init_rs232(volatile avr32_usart_t *usart, const usart_options_t *opt, long pba_hz)
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159 // Reset the USART and shutdown TX and RX.
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160 usart_reset(usart);
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162 // Check input values.
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163 if (!opt) // Null pointer.
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164 return USART_INVALID_INPUT;
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165 if (opt->charlength < 5 || opt->charlength > 9 ||
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166 opt->paritytype > 7 ||
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167 opt->stopbits > 2 + 255 ||
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168 opt->channelmode > 3)
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169 return USART_INVALID_INPUT;
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171 if (usart_set_baudrate(usart, opt->baudrate, pba_hz) == USART_INVALID_INPUT)
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172 return USART_INVALID_INPUT;
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174 if (opt->charlength == 9)
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176 // Character length set to 9 bits. MODE9 dominates CHRL.
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177 usart->mr |= AVR32_USART_MR_MODE9_MASK;
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181 // CHRL gives the character length (- 5) when MODE9 = 0.
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182 usart->mr |= (opt->charlength - 5) << AVR32_USART_MR_CHRL_OFFSET;
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185 usart->mr |= (opt->channelmode << AVR32_USART_MR_CHMODE_OFFSET) |
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186 (opt->paritytype << AVR32_USART_MR_PAR_OFFSET);
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188 if (opt->stopbits > USART_2_STOPBITS)
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190 // Set two stop bits
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191 usart->mr |= AVR32_USART_MR_NBSTOP_2 << AVR32_USART_MR_NBSTOP_OFFSET;
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192 // and a timeguard period gives the rest.
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193 usart->ttgr = opt->stopbits - USART_2_STOPBITS;
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196 // Insert 1, 1.5 or 2 stop bits.
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197 usart->mr |= opt->stopbits << AVR32_USART_MR_NBSTOP_OFFSET;
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199 // Setup complete; enable communication.
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200 // Enable input and output.
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201 usart->cr |= AVR32_USART_CR_TXEN_MASK |
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202 AVR32_USART_CR_RXEN_MASK;
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204 return USART_SUCCESS;
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208 int usart_init_hw_handshaking(volatile avr32_usart_t *usart, const usart_options_t *opt, long pba_hz)
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210 // First: Setup standard RS232.
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211 if (usart_init_rs232(usart, opt, pba_hz) == USART_INVALID_INPUT)
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212 return USART_INVALID_INPUT;
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214 // Clear previous mode.
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215 usart->mr &= ~AVR32_USART_MR_MODE_MASK;
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216 // Hardware handshaking.
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217 usart->mr |= USART_MODE_HW_HSH << AVR32_USART_MR_MODE_OFFSET;
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219 return USART_SUCCESS;
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223 int usart_init_IrDA(volatile avr32_usart_t *usart, const usart_options_t *opt,
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224 long pba_hz, unsigned char irda_filter)
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226 // First: Setup standard RS232.
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227 if (usart_init_rs232(usart, opt, pba_hz) == USART_INVALID_INPUT)
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228 return USART_INVALID_INPUT;
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230 // Set IrDA counter.
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231 usart->ifr = irda_filter;
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233 // Activate "low-pass filtering" of input.
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234 usart->mr |= AVR32_USART_MR_FILTER_MASK;
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236 return USART_SUCCESS;
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240 int usart_init_modem(volatile avr32_usart_t *usart, const usart_options_t *opt, long pba_hz)
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242 // First: Setup standard RS232.
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243 if (usart_init_rs232(usart, opt, pba_hz) == USART_INVALID_INPUT)
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244 return USART_INVALID_INPUT;
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246 // Clear previous mode.
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247 usart->mr &= ~AVR32_USART_MR_MODE_MASK;
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249 usart->mr |= USART_MODE_MODEM << AVR32_USART_MR_MODE_OFFSET;
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251 return USART_SUCCESS;
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255 int usart_init_rs485(volatile avr32_usart_t *usart, const usart_options_t *opt, long pba_hz)
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257 // First: Setup standard RS232.
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258 if (usart_init_rs232(usart, opt, pba_hz) == USART_INVALID_INPUT)
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259 return USART_INVALID_INPUT;
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261 // Clear previous mode.
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262 usart->mr &= ~AVR32_USART_MR_MODE_MASK;
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264 usart->mr |= USART_MODE_RS485 << AVR32_USART_MR_MODE_OFFSET;
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266 return USART_SUCCESS;
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270 int usart_init_iso7816(volatile avr32_usart_t *usart, const iso7816_options_t *opt, int t, long pba_hz)
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272 // Reset the USART and shutdown TX and RX.
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273 usart_reset(usart);
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275 // Check input values.
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276 if (!opt) // Null pointer.
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277 return USART_INVALID_INPUT;
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281 // Set USART mode to ISO7816, T=0.
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282 // The T=0 protocol always uses 2 stop bits.
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283 usart->mr = (USART_MODE_ISO7816_T0 << AVR32_USART_MR_MODE_OFFSET) |
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284 (AVR32_USART_MR_NBSTOP_2 << AVR32_USART_MR_NBSTOP_OFFSET) |
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285 (opt->bit_order << AVR32_USART_MR_MSBF_OFFSET); // Allow MSBF in T=0.
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289 // Only LSB first in the T=1 protocol.
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290 // max_iterations field is only used in T=0 mode.
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291 if (opt->bit_order != 0 ||
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292 opt->max_iterations != 0)
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293 return USART_INVALID_INPUT;
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294 // Set USART mode to ISO7816, T=1.
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295 // The T=1 protocol always uses 1 stop bit.
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296 usart->mr = (USART_MODE_ISO7816_T1 << AVR32_USART_MR_MODE_OFFSET) |
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297 (AVR32_USART_MR_NBSTOP_1 << AVR32_USART_MR_NBSTOP_OFFSET);
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300 return USART_INVALID_INPUT;
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302 if (usart_set_baudrate(usart, opt->iso7816_hz, pba_hz) == USART_INVALID_INPUT)
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303 return USART_INVALID_INPUT;
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305 // Set FIDI register: bit rate = selected clock/FI_DI_ratio/16.
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306 usart->fidi = opt->fidi_ratio;
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307 // Set ISO7816 spesific options in the MODE register.
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308 usart->mr |= (opt->inhibit_nack << AVR32_USART_MR_INACK_OFFSET) |
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309 (opt->dis_suc_nack << AVR32_USART_MR_DSNACK_OFFSET) |
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310 (opt->max_iterations << AVR32_USART_MR_MAX_ITERATION_OFFSET) |
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311 AVR32_USART_MR_CLKO_MASK; // Enable clock output.
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313 // Setup complete; enable input.
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314 // Leave TX disabled for now.
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315 usart->cr |= AVR32_USART_CR_RXEN_MASK;
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317 return USART_SUCCESS;
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322 //------------------------------------------------------------------------------
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323 /*! \name Transmit/Receive Functions
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328 int usart_send_address(volatile avr32_usart_t *usart, int address)
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330 // Check if USART is in multidrop / RS485 mode.
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331 if (!usart_mode_is_multidrop(usart)) return USART_MODE_FAULT;
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333 // Prepare to send an address.
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334 usart->cr |= AVR32_USART_CR_SENDA_MASK;
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336 // Write the address to TX.
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337 usart_bw_write_char(usart, address);
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339 return USART_SUCCESS;
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343 int usart_write_char(volatile avr32_usart_t *usart, int c)
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345 if (usart->csr & AVR32_USART_CSR_TXRDY_MASK)
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348 return USART_SUCCESS;
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351 return USART_TX_BUSY;
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355 int usart_putchar(volatile avr32_usart_t *usart, int c)
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357 int timeout = USART_DEFAULT_TIMEOUT;
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363 if (!timeout--) return USART_FAILURE;
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364 } while (usart_write_char(usart, '\r') != USART_SUCCESS);
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366 timeout = USART_DEFAULT_TIMEOUT;
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371 if (!timeout--) return USART_FAILURE;
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372 } while (usart_write_char(usart, c) != USART_SUCCESS);
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374 return USART_SUCCESS;
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378 int usart_read_char(volatile avr32_usart_t *usart, int *c)
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380 // Check for errors: frame, parity and overrun. In RS485 mode, a parity error
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381 // would mean that an address char has been received.
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382 if (usart->csr & (AVR32_USART_CSR_OVRE_MASK |
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383 AVR32_USART_CSR_FRAME_MASK |
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384 AVR32_USART_CSR_PARE_MASK))
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385 return USART_RX_ERROR;
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387 // No error; if we really did receive a char, read it and return SUCCESS.
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388 if (usart->csr & AVR32_USART_CSR_RXRDY_MASK)
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390 *c = (unsigned short)usart->rhr;
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391 return USART_SUCCESS;
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394 return USART_RX_EMPTY;
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398 int usart_getchar(volatile avr32_usart_t *usart)
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402 while ((ret = usart_read_char(usart, &c)) == USART_RX_EMPTY);
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404 if (ret == USART_RX_ERROR)
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405 return USART_FAILURE;
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411 void usart_write_line(volatile avr32_usart_t *usart, const char *string)
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413 while (*string != '\0')
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414 usart_putchar(usart, *string++);
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418 int usart_get_echo_line(volatile avr32_usart_t *usart)
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421 int retval = USART_SUCCESS;
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425 rx_char = usart_getchar(usart);
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426 if (rx_char == USART_FAILURE)
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428 usart_write_line(usart, "Error!!!\n");
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431 if (rx_char == '\x03')
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433 retval = USART_FAILURE;
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436 usart_putchar(usart, rx_char);
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437 if (rx_char == '\r')
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439 usart_putchar(usart, '\n');
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