From ca35947f8132f1879b2706ecceb82c112bfe0f71 Mon Sep 17 00:00:00 2001 From: "Konstantin K. Oblaukhov" Date: Tue, 20 Nov 2018 09:52:01 +0700 Subject: Reorganize NRF5x driver files. --- os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c | 389 ++++++++++++++++++++++++++++++ os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.h | 238 ++++++++++++++++++ 2 files changed, 627 insertions(+) create mode 100644 os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c create mode 100644 os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.h (limited to 'os/hal/ports/NRF5/LLD/SPIv1') diff --git a/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c b/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c new file mode 100644 index 0000000..95bb9b7 --- /dev/null +++ b/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c @@ -0,0 +1,389 @@ +/* + Copyright (C) 2015 Stephen Caudle + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +*/ + +/** + * @file SPIv1/hal_spi_lld.c + * @brief NRF5 low level SPI driver code. + * + * @addtogroup SPI + * @{ + */ + +#include "hal.h" + +#if HAL_USE_SPI || defined(__DOXYGEN__) + +/*===========================================================================*/ +/* Driver exported variables. */ +/*===========================================================================*/ + +#if NRF5_SPI_USE_SPI0 || defined(__DOXYGEN__) +/** @brief SPI1 driver identifier.*/ +SPIDriver SPID1; +#endif + +#if NRF5_SPI_USE_SPI1 || defined(__DOXYGEN__) +/** @brief SPI2 driver identifier.*/ +SPIDriver SPID2; +#endif + +/*===========================================================================*/ +/* Driver local variables and types. */ +/*===========================================================================*/ + +/*===========================================================================*/ +/* Driver local functions. */ +/*===========================================================================*/ + +/** + * @brief Preloads the transmit FIFO. + * + * @param[in] spip pointer to the @p SPIDriver object + */ +static void port_fifo_preload(SPIDriver *spip) { + NRF_SPI_Type *port = spip->port; + + if (spip->txcnt > 0 && spip->txptr != NULL) + port->TXD = *(uint8_t *)spip->txptr++; + else + port->TXD = 0xFF; + spip->txcnt--; +} + +#if defined(__GNUC__) +__attribute__((noinline)) +#endif +/** + * @brief Common IRQ handler. + * + * @param[in] spip pointer to the @p SPIDriver object + */ +static void serve_interrupt(SPIDriver *spip) { + NRF_SPI_Type *port = spip->port; + + // Clear SPI READY event flag + port->EVENTS_READY = 0; +#if CORTEX_MODEL >= 4 + (void)port->EVENTS_READY; +#endif + + if (spip->rxptr != NULL) { + *(uint8_t *)spip->rxptr++ = port->RXD; + } + else { + (void)port->RXD; + if (--spip->rxcnt == 0) { + osalDbgAssert(spip->txcnt == 0, "counter out of synch"); + /* Stops the IRQ sources.*/ + spip->port->INTENCLR = (SPI_INTENCLR_READY_Clear << SPI_INTENCLR_READY_Pos); + /* Portable SPI ISR code defined in the high level driver, note, it is + a macro.*/ + _spi_isr_code(spip); + return; + } + } + if (spip->txcnt > 0) { + port_fifo_preload(spip); + } + else { + spip->port->INTENCLR = (SPI_INTENCLR_READY_Clear << SPI_INTENCLR_READY_Pos); + /* Portable SPI ISR code defined in the high level driver, note, it is + a macro.*/ + _spi_isr_code(spip); + } +} + +/*===========================================================================*/ +/* Driver interrupt handlers. */ +/*===========================================================================*/ + +#if NRF5_SPI_USE_SPI0 || defined(__DOXYGEN__) +/** + * @brief SPI0 interrupt handler. + * + * @isr + */ +CH_IRQ_HANDLER(Vector4C) { + + CH_IRQ_PROLOGUE(); + serve_interrupt(&SPID1); + CH_IRQ_EPILOGUE(); +} +#endif +#if NRF5_SPI_USE_SPI1 || defined(__DOXYGEN__) +/** + * @brief SPI1 interrupt handler. + * + * @isr + */ +CH_IRQ_HANDLER(Vector50) { + + CH_IRQ_PROLOGUE(); + serve_interrupt(&SPID2); + CH_IRQ_EPILOGUE(); +} +#endif + +/*===========================================================================*/ +/* Driver exported functions. */ +/*===========================================================================*/ + +/** + * @brief Low level SPI driver initialization. + * + * @notapi + */ +void spi_lld_init(void) { + +#if NRF5_SPI_USE_SPI0 + spiObjectInit(&SPID1); + SPID1.port = NRF_SPI0; +#endif +#if NRF5_SPI_USE_SPI1 + spiObjectInit(&SPID2); + SPID2.port = NRF_SPI1; +#endif +} + +/** + * @brief Configures and activates the SPI peripheral. + * + * @param[in] spip pointer to the @p SPIDriver object + * + * @notapi + */ +void spi_lld_start(SPIDriver *spip) { + uint32_t config; + + if (spip->state == SPI_STOP) { +#if NRF5_SPI_USE_SPI0 + if (&SPID1 == spip) + nvicEnableVector(SPI0_TWI0_IRQn, NRF5_SPI_SPI0_IRQ_PRIORITY); +#endif +#if NRF5_SPI_USE_SPI1 + if (&SPID2 == spip) + nvicEnableVector(SPI1_TWI1_IRQn, NRF5_SPI_SPI1_IRQ_PRIORITY); +#endif + } + + config = spip->config->lsbfirst ? + (SPI_CONFIG_ORDER_LsbFirst << SPI_CONFIG_ORDER_Pos) : + (SPI_CONFIG_ORDER_MsbFirst << SPI_CONFIG_ORDER_Pos); + + switch (spip->config->mode) { + case 1: + config |= (SPI_CONFIG_CPOL_ActiveLow << SPI_CONFIG_CPOL_Pos); + config |= (SPI_CONFIG_CPHA_Trailing << SPI_CONFIG_CPHA_Pos); + break; + case 2: + config |= (SPI_CONFIG_CPOL_ActiveHigh << SPI_CONFIG_CPOL_Pos); + config |= (SPI_CONFIG_CPHA_Leading << SPI_CONFIG_CPHA_Pos); + break; + case 3: + config |= (SPI_CONFIG_CPOL_ActiveHigh << SPI_CONFIG_CPOL_Pos); + config |= (SPI_CONFIG_CPHA_Trailing << SPI_CONFIG_CPHA_Pos); + break; + default: + config |= (SPI_CONFIG_CPOL_ActiveLow << SPI_CONFIG_CPOL_Pos); + config |= (SPI_CONFIG_CPHA_Leading << SPI_CONFIG_CPHA_Pos); + break; + } + + /* Configuration.*/ + spip->port->CONFIG = config; +#if NRF_SERIES == 51 + spip->port->PSELSCK = spip->config->sckpad; + spip->port->PSELMOSI = spip->config->mosipad; + spip->port->PSELMISO = spip->config->misopad; +#else + spip->port->PSEL.SCK = spip->config->sckpad; + spip->port->PSEL.MOSI = spip->config->mosipad; + spip->port->PSEL.MISO = spip->config->misopad; +#endif + spip->port->FREQUENCY = spip->config->freq; + spip->port->ENABLE = (SPI_ENABLE_ENABLE_Enabled << SPI_ENABLE_ENABLE_Pos); + + /* clear events flag */ + spip->port->EVENTS_READY = 0; +#if CORTEX_MODEL >= 4 + (void)spip->port->EVENTS_READY; +#endif +} + +/** + * @brief Deactivates the SPI peripheral. + * + * @param[in] spip pointer to the @p SPIDriver object + * + * @notapi + */ +void spi_lld_stop(SPIDriver *spip) { + + if (spip->state != SPI_STOP) { + spip->port->ENABLE = (SPI_ENABLE_ENABLE_Disabled << SPI_ENABLE_ENABLE_Pos); + spip->port->INTENCLR = (SPI_INTENCLR_READY_Clear << SPI_INTENCLR_READY_Pos); +#if NRF5_SPI_USE_SPI0 + if (&SPID1 == spip) + nvicDisableVector(SPI0_TWI0_IRQn); +#endif +#if NRF5_SPI_USE_SPI1 + if (&SPID2 == spip) + nvicDisableVector(SPI1_TWI1_IRQn); +#endif + } +} + +/** + * @brief Asserts the slave select signal and prepares for transfers. + * + * @param[in] spip pointer to the @p SPIDriver object + * + * @notapi + */ +void spi_lld_select(SPIDriver *spip) { + + palClearPad(IOPORT1, spip->config->sspad); +} + +/** + * @brief Deasserts the slave select signal. + * @details The previously selected peripheral is unselected. + * + * @param[in] spip pointer to the @p SPIDriver object + * + * @notapi + */ +void spi_lld_unselect(SPIDriver *spip) { + + palSetPad(IOPORT1, spip->config->sspad); +} + +/** + * @brief Ignores data on the SPI bus. + * @details This function transmits a series of idle words on the SPI bus and + * ignores the received data. This function can be invoked even + * when a slave select signal has not been yet asserted. + * + * @param[in] spip pointer to the @p SPIDriver object + * @param[in] n number of words to be ignored + * + * @notapi + */ +void spi_lld_ignore(SPIDriver *spip, size_t n) { + + spip->rxptr = NULL; + spip->txptr = NULL; + spip->rxcnt = spip->txcnt = n; + port_fifo_preload(spip); + spip->port->INTENSET = (SPI_INTENCLR_READY_Enabled << SPI_INTENCLR_READY_Pos); +} + +/** + * @brief Exchanges data on the SPI bus. + * @details This asynchronous function starts a simultaneous transmit/receive + * operation. + * @post At the end of the operation the configured callback is invoked. + * @note The buffers are organized as uint8_t arrays for data sizes below or + * equal to 8 bits else it is organized as uint16_t arrays. + * + * @param[in] spip pointer to the @p SPIDriver object + * @param[in] n number of words to be exchanged + * @param[in] txbuf the pointer to the transmit buffer + * @param[out] rxbuf the pointer to the receive buffer + * + * @notapi + */ +void spi_lld_exchange(SPIDriver *spip, size_t n, + const void *txbuf, void *rxbuf) { + + spip->rxptr = rxbuf; + spip->txptr = txbuf; + spip->rxcnt = spip->txcnt = n; + port_fifo_preload(spip); + spip->port->INTENSET = (SPI_INTENCLR_READY_Enabled << SPI_INTENCLR_READY_Pos); +} + +/** + * @brief Sends data over the SPI bus. + * @details This asynchronous function starts a transmit operation. + * @post At the end of the operation the configured callback is invoked. + * @note The buffers are organized as uint8_t arrays for data sizes below or + * equal to 8 bits else it is organized as uint16_t arrays. + * + * @param[in] spip pointer to the @p SPIDriver object + * @param[in] n number of words to send + * @param[in] txbuf the pointer to the transmit buffer + * + * @notapi + */ +void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) { + + spip->rxptr = NULL; + spip->txptr = txbuf; + spip->rxcnt = spip->txcnt = n; + port_fifo_preload(spip); + spip->port->INTENSET = (SPI_INTENCLR_READY_Enabled << SPI_INTENCLR_READY_Pos); +} + +/** + * @brief Receives data from the SPI bus. + * @details This asynchronous function starts a receive operation. + * @post At the end of the operation the configured callback is invoked. + * @note The buffers are organized as uint8_t arrays for data sizes below or + * equal to 8 bits else it is organized as uint16_t arrays. + * + * @param[in] spip pointer to the @p SPIDriver object + * @param[in] n number of words to receive + * @param[out] rxbuf the pointer to the receive buffer + * + * @notapi + */ +void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) { + + spip->rxptr = rxbuf; + spip->txptr = NULL; + spip->rxcnt = spip->txcnt = n; + port_fifo_preload(spip); + spip->port->INTENSET = (SPI_INTENCLR_READY_Enabled << SPI_INTENCLR_READY_Pos); +} + +/** + * @brief Exchanges one frame using a polled wait. + * @details This synchronous function exchanges one frame using a polled + * synchronization method. This function is useful when exchanging + * small amount of data on high speed channels, usually in this + * situation is much more efficient just wait for completion using + * polling than suspending the thread waiting for an interrupt. + * + * @param[in] spip pointer to the @p SPIDriver object + * @param[in] frame the data frame to send over the SPI bus + * @return The received data frame from the SPI bus. + */ +uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) { + + spip->port->TXD = (uint8_t)frame; + while (spip->port->EVENTS_READY == 0) + ; + spip->port->EVENTS_READY = 0; +#if CORTEX_MODEL >= 4 + (void)spip->port->EVENTS_READY; +#endif + return spip->port->RXD; +} + +#endif /* HAL_USE_SPI */ + +/** @} */ diff --git a/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.h b/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.h new file mode 100644 index 0000000..1c6d858 --- /dev/null +++ b/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.h @@ -0,0 +1,238 @@ +/* + Copyright (C) 2015 Stephen Caudle + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +*/ + +/** + * @file SPIv1/hal_spi_lld.h + * @brief NRF5 low level SPI driver header. + * + * @addtogroup SPI + * @{ + */ + +#ifndef HAL_SPI_LLD_H +#define HAL_SPI_LLD_H + +#if HAL_USE_SPI || defined(__DOXYGEN__) + +/*===========================================================================*/ +/* Driver constants. */ +/*===========================================================================*/ + +/*===========================================================================*/ +/* Driver pre-compile time settings. */ +/*===========================================================================*/ + +/** + * @brief SPI0 interrupt priority level setting. + */ +#if !defined(NRF5_SPI_SPI0_IRQ_PRIORITY) || defined(__DOXYGEN__) +#define NRF5_SPI_SPI0_IRQ_PRIORITY 3 +#endif + +/** + * @brief SPI1 interrupt priority level setting. + */ +#if !defined(NRF5_SPI_SPI1_IRQ_PRIORITY) || defined(__DOXYGEN__) +#define NRF5_SPI_SPI1_IRQ_PRIORITY 3 +#endif + +/** + * @brief Overflow error hook. + * @details The default action is to stop the system. + */ +#if !defined(NRF5_SPI_SPI_ERROR_HOOK) || defined(__DOXYGEN__) +#define NRF5_SPI_SPI_ERROR_HOOK() chSysHalt() +#endif + +/*===========================================================================*/ +/* Derived constants and error checks. */ +/*===========================================================================*/ + +#if !NRF5_SPI_USE_SPI0 && !NRF5_SPI_USE_SPI1 +#error "SPI driver activated but no SPI peripheral assigned" +#endif + +#if NRF5_SPI_USE_SPI0 && \ + !OSAL_IRQ_IS_VALID_PRIORITY(NRF5_SPI_SPI0_IRQ_PRIORITY) +#error "Invalid IRQ priority assigned to SPI0" +#endif + +#if NRF5_SPI_USE_SPI1 && \ + !OSAL_IRQ_IS_VALID_PRIORITY(NRF5_SPI_SPI1_IRQ_PRIORITY) +#error "Invalid IRQ priority assigned to SPI1" +#endif + +/*===========================================================================*/ +/* Driver data structures and types. */ +/*===========================================================================*/ + +/** + * @brief Type of a structure representing an SPI driver. + */ +typedef struct SPIDriver SPIDriver; + +/** + * @brief SPI notification callback type. + * + * @param[in] spip pointer to the @p SPIDriver object triggering the + * callback + */ +typedef void (*spicallback_t)(SPIDriver *spip); + +/** + * @brief SPI frequency + */ +typedef enum { + NRF5_SPI_FREQ_125KBPS = (SPI_FREQUENCY_FREQUENCY_K125 << SPI_FREQUENCY_FREQUENCY_Pos), + NRF5_SPI_FREQ_250KBPS = (SPI_FREQUENCY_FREQUENCY_K250 << SPI_FREQUENCY_FREQUENCY_Pos), + NRF5_SPI_FREQ_500KBPS = (SPI_FREQUENCY_FREQUENCY_K500 << SPI_FREQUENCY_FREQUENCY_Pos), + NRF5_SPI_FREQ_1MBPS = (SPI_FREQUENCY_FREQUENCY_M1 << SPI_FREQUENCY_FREQUENCY_Pos), + NRF5_SPI_FREQ_2MBPS = (SPI_FREQUENCY_FREQUENCY_M2 << SPI_FREQUENCY_FREQUENCY_Pos), + NRF5_SPI_FREQ_4MBPS = (SPI_FREQUENCY_FREQUENCY_M4 << SPI_FREQUENCY_FREQUENCY_Pos), + NRF5_SPI_FREQ_8MBPS = (SPI_FREQUENCY_FREQUENCY_M8 << SPI_FREQUENCY_FREQUENCY_Pos), +} spifreq_t; + +/** + * @brief Driver configuration structure. + */ +typedef struct { + /** + * @brief Operation complete callback or @p NULL. + */ + spicallback_t end_cb; + /** + * @brief The frequency of the SPI peripheral + */ + spifreq_t freq; + /** + * @brief The SCK pad + */ + uint16_t sckpad; + /** + * @brief The MOSI pad + */ + uint16_t mosipad; + /** + * @brief The MOSI pad + */ + uint16_t misopad; + /* End of the mandatory fields.*/ + /** + * @brief The chip select line pad number. + */ + uint16_t sspad; + /** + * @brief Shift out least significant bit first + */ + uint8_t lsbfirst; + /** + * @brief SPI mode + */ + uint8_t mode; +} SPIConfig; + +/** + * @brief Structure representing a SPI driver. + */ +struct SPIDriver { + /** + * @brief Driver state. + */ + spistate_t state; + /** + * @brief Current configuration data. + */ + const SPIConfig *config; +#if SPI_USE_WAIT || defined(__DOXYGEN__) + /** + * @brief Waiting thread. + */ + thread_reference_t thread; +#endif /* SPI_USE_WAIT */ +#if SPI_USE_MUTUAL_EXCLUSION || defined(__DOXYGEN__) +#if CH_CFG_USE_MUTEXES || defined(__DOXYGEN__) + /** + * @brief Mutex protecting the bus. + */ + mutex_t mutex; +#elif CH_CFG_USE_SEMAPHORES + semaphore_t semaphore; +#endif +#endif /* SPI_USE_MUTUAL_EXCLUSION */ +#if defined(SPI_DRIVER_EXT_FIELDS) + SPI_DRIVER_EXT_FIELDS +#endif + /* End of the mandatory fields.*/ + /** + * @brief Pointer to the SPI port. + */ + NRF_SPI_Type *port; + /** + * @brief Number of bytes yet to be received. + */ + uint32_t rxcnt; + /** + * @brief Receive pointer or @p NULL. + */ + void *rxptr; + /** + * @brief Number of bytes yet to be transmitted. + */ + uint32_t txcnt; + /** + * @brief Transmit pointer or @p NULL. + */ + const void *txptr; +}; + +/*===========================================================================*/ +/* Driver macros. */ +/*===========================================================================*/ + +/*===========================================================================*/ +/* External declarations. */ +/*===========================================================================*/ + +#if NRF5_SPI_USE_SPI0 && !defined(__DOXYGEN__) +extern SPIDriver SPID1; +#endif +#if NRF5_SPI_USE_SPI1 && !defined(__DOXYGEN__) +extern SPIDriver SPID2; +#endif + +#ifdef __cplusplus +extern "C" { +#endif + void spi_lld_init(void); + void spi_lld_start(SPIDriver *spip); + void spi_lld_stop(SPIDriver *spip); + void spi_lld_select(SPIDriver *spip); + void spi_lld_unselect(SPIDriver *spip); + void spi_lld_ignore(SPIDriver *spip, size_t n); + void spi_lld_exchange(SPIDriver *spip, size_t n, + const void *txbuf, void *rxbuf); + void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf); + void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf); + uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame); +#ifdef __cplusplus +} +#endif + +#endif /* HAL_USE_SPI */ + +#endif /* HAL_SPI_LLD_H */ + +/** @} */ -- cgit v1.2.3 From f4d6d909898e777efaa2d479095e41cd2045621d Mon Sep 17 00:00:00 2001 From: Konstantin Oblaukhov Date: Sat, 29 Sep 2018 16:33:50 +0700 Subject: NRF5x platform - new Makefiles. --- os/hal/ports/NRF5/LLD/SPIv1/driver.mk | 9 +++++++++ 1 file changed, 9 insertions(+) create mode 100644 os/hal/ports/NRF5/LLD/SPIv1/driver.mk (limited to 'os/hal/ports/NRF5/LLD/SPIv1') diff --git a/os/hal/ports/NRF5/LLD/SPIv1/driver.mk b/os/hal/ports/NRF5/LLD/SPIv1/driver.mk new file mode 100644 index 0000000..d583a68 --- /dev/null +++ b/os/hal/ports/NRF5/LLD/SPIv1/driver.mk @@ -0,0 +1,9 @@ +ifeq ($(USE_SMART_BUILD),yes) +ifneq ($(findstring HAL_USE_SPI TRUE,$(HALCONF)),) +PLATFORMSRC_CONTRIB += ${CHIBIOS_CONTRIB}/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c +endif +else +PLATFORMSRC_CONTRIB += ${CHIBIOS_CONTRIB}/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c +endif + +PLATFORMINC_CONTRIB += ${CHIBIOS_CONTRIB}/os/hal/ports/NRF5/LLD/SPIv1 -- cgit v1.2.3 From 9b5eba54fb0789b31e967582ab55a307af821b08 Mon Sep 17 00:00:00 2001 From: Fabio D'Urso Date: Tue, 23 Jul 2019 01:02:52 +0200 Subject: NRF: Make the SPI driver compile on NRF52 too --- os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'os/hal/ports/NRF5/LLD/SPIv1') diff --git a/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c b/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c index 95bb9b7..3e0bc83 100644 --- a/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c +++ b/os/hal/ports/NRF5/LLD/SPIv1/hal_spi_lld.c @@ -26,6 +26,11 @@ #if HAL_USE_SPI || defined(__DOXYGEN__) +#if NRF_SERIES == 52 +#define SPI0_TWI0_IRQn SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQn +#define SPI1_TWI1_IRQn SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1_IRQn +#endif + /*===========================================================================*/ /* Driver exported variables. */ /*===========================================================================*/ -- cgit v1.2.3