mirror of https://github.com/ARMmbed/mbed-os.git
[STM32F3xx] Change SPI clock selection
Update of STM32F3 family CPI clock selection algo. Maximum SPI clock is obtained from APB domain clock (based on HAL API). Then algo sets maximum frequency available below requested frequency Signed-off-by: Erwan GOURIOU <frq07517@st.com>pull/2013/head
Erwan GOURIOU
parent
837cb78b39
commit
c87ff7872a
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@ -28,6 +28,7 @@
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*******************************************************************************
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*/
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#include "mbed_assert.h"
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#include "mbed_error.h"
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#include "spi_api.h"
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#if DEVICE_SPI
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@ -195,86 +196,52 @@ void spi_format(spi_t *obj, int bits, int mode, int slave)
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init_spi(obj);
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}
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static const uint16_t baudrate_prescaler_table[] = {SPI_BAUDRATEPRESCALER_2,
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SPI_BAUDRATEPRESCALER_4,
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SPI_BAUDRATEPRESCALER_8,
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SPI_BAUDRATEPRESCALER_16,
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SPI_BAUDRATEPRESCALER_32,
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SPI_BAUDRATEPRESCALER_64,
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SPI_BAUDRATEPRESCALER_128,
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SPI_BAUDRATEPRESCALER_256};
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void spi_frequency(spi_t *obj, int hz)
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{
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#if defined(TARGET_STM32F334C8)
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// Values depend of APB2CLK : 64 MHz if HSI is used, 72 MHz if HSE is used
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if (hz < 500000) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_256; // 250 kHz - 281 kHz
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} else if ((hz >= 500000) && (hz < 1000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_128; // 500 kHz - 563 kHz
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} else if ((hz >= 1000000) && (hz < 2000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_64; // 1 MHz - 1.13 MHz
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} else if ((hz >= 2000000) && (hz < 4000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_32; // 2 MHz - 2.25 MHz
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} else if ((hz >= 4000000) && (hz < 8000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_16; // 4 MHz - 4.5 MHz
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} else if ((hz >= 8000000) && (hz < 16000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_8; // 8 MHz - 9 MHz
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} else if ((hz >= 16000000) && (hz < 32000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_4; // 16 MHz - 18 MHz
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} else { // >= 32000000
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obj->br_presc = SPI_BAUDRATEPRESCALER_2; // 32 MHz - 36 MHz
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}
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#elif defined(TARGET_STM32F302R8)
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if (hz < 250000) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_256; // 125 kHz - 141 kHz
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} else if ((hz >= 250000) && (hz < 500000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_128; // 250 kHz - 280 kHz
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} else if ((hz >= 500000) && (hz < 1000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_64; // 500 kHz - 560 kHz
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} else if ((hz >= 1000000) && (hz < 2000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_32; // 1 MHz - 1.13 MHz
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} else if ((hz >= 2000000) && (hz < 4000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_16; // 2 MHz - 2.25 MHz
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} else if ((hz >= 4000000) && (hz < 8000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_8; // 4 MHz - 4.5 MHz
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} else if ((hz >= 8000000) && (hz < 16000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_4; // 8 MHz - 9 MHz
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} else { // >= 16000000
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obj->br_presc = SPI_BAUDRATEPRESCALER_2; // 16 MHz - 18 MHz
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int spi_hz = 0;
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uint8_t prescaler_rank = 0;
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/* Get source clock depending on SPI instance */
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switch ((int)obj->spi) {
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#if defined SPI1_BASE
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case SPI_1:
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/* SPI_1. Source CLK is PCKL2 */
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spi_hz = HAL_RCC_GetPCLK2Freq();
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break;
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#endif
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#if defined SPI2_BASE
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case SPI_2:
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#endif
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#if defined SPI3_BASE
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case SPI_3:
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#endif
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/* SPI_2 and SPI_3. Source CLK is PCKL1 */
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spi_hz = HAL_RCC_GetPCLK1Freq();
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break;
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default:
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error("SPI instance not set");
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}
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#else
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// Values depend of APB1CLK and APB2CLK : 32 MHz if HSI is used, 36 MHz if HSE is used
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if (obj->spi == SPI_1) {
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if (hz < 500000) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_256; // 250 kHz - 280 kHz
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} else if ((hz >= 500000) && (hz < 1000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_128; // 500 kHz - 560 kHz
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} else if ((hz >= 1000000) && (hz < 2000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_64; // 1 MHz - 1.13 MHz
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} else if ((hz >= 2000000) && (hz < 4000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_32; // 2 MHz - 2.25 MHz
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} else if ((hz >= 4000000) && (hz < 8000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_16; // 4 MHz - 4.5 MHz
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} else if ((hz >= 8000000) && (hz < 16000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_8; // 8 MHz - 9 MHz
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} else if ((hz >= 16000000) && (hz < 32000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_4; // 16 MHz - 18 MHz
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} else { // >= 32000000
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obj->br_presc = SPI_BAUDRATEPRESCALER_2; // 32 MHz - 36 MHz
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}
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} else {
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if (hz < 250000) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_256; // 125 kHz - 141 kHz
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} else if ((hz >= 250000) && (hz < 500000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_128; // 250 kHz - 280 kHz
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} else if ((hz >= 500000) && (hz < 1000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_64; // 500 kHz - 560 kHz
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} else if ((hz >= 1000000) && (hz < 2000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_32; // 1 MHz - 1.13 MHz
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} else if ((hz >= 2000000) && (hz < 4000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_16; // 2 MHz - 2.25 MHz
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} else if ((hz >= 4000000) && (hz < 8000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_8; // 4 MHz - 4.5 MHz
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} else if ((hz >= 8000000) && (hz < 16000000)) {
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obj->br_presc = SPI_BAUDRATEPRESCALER_4; // 8 MHz - 9 MHz
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} else { // >= 16000000
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obj->br_presc = SPI_BAUDRATEPRESCALER_2; // 16 MHz - 18 MHz
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}
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}
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#endif
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/* Define pre-scaler in order to get highest available frequency below requested frequency */
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while ((spi_hz > hz) && (prescaler_rank < sizeof(baudrate_prescaler_table)/sizeof(baudrate_prescaler_table[0]))){
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spi_hz = spi_hz / 2;
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prescaler_rank++;
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}
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if (prescaler_rank <= sizeof(baudrate_prescaler_table)/sizeof(baudrate_prescaler_table[0])) {
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obj->br_presc = baudrate_prescaler_table[prescaler_rank-1];
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} else {
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error("Couldn't setup requested SPI frequency");
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}
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init_spi(obj);
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}
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