From cb115186c5269f6463a1a4b422e7a0b9e9f5c6b7 Mon Sep 17 00:00:00 2001 From: ergosys Date: Thu, 11 Dec 2014 23:34:08 -0800 Subject: Improve SSD1306 spi example Don't acquire bus for every command Use SPI driver to control chip select Use SPI driver start/stop only when bus acquired for lower power usage Throttle SPI speed based on processor clock --- boards/addons/gdisp/board_SSD1306_spi.h | 153 ++++++++++++++------------------ 1 file changed, 66 insertions(+), 87 deletions(-) (limited to 'boards') diff --git a/boards/addons/gdisp/board_SSD1306_spi.h b/boards/addons/gdisp/board_SSD1306_spi.h index 56e1abae..5b647578 100644 --- a/boards/addons/gdisp/board_SSD1306_spi.h +++ b/boards/addons/gdisp/board_SSD1306_spi.h @@ -16,65 +16,60 @@ #ifndef _GDISP_LLD_BOARD_H #define _GDISP_LLD_BOARD_H -// The command byte to put on the front of each page line -#define SSD1306_PAGE_PREFIX 0x40 // Co = 0, D/C = 1 - -// For a multiple display configuration we would put all this in a structure and then -// set g->board to that structure. -#define SSD1306_RESET_PORT GPIOB -#define SSD1306_RESET_PIN 5 -#define SSD1306_MISO_PORT GPIOB -#define SSD1306_MISO_PIN 8 -#define SSD1306_MOSI_PORT GPIOB -#define SSD1306_MOSI_PIN 7 -#define SSD1306_SCK_PORT GPIOB -#define SSD1306_SCK_PIN 6 -#define SSD1306_CS_PORT GPIOB -#define SSD1306_CS_PIN 5 -#define SET_RST palSetPad(SSD1306_RESET_PORT, SSD1306_RESET_PIN); -#define CLR_RST palClearPad(SSD1306_RESET_PORT, SSD1306_RESET_PIN); +// Pin & SPI setup -/* - * SPI1 configuration structure. - * Speed 42MHz, CPHA=0, CPOL=0, 8bits frames, MSb transmitted first. - * The slave select line is the pin 4 on the port GPIOA. - */ -static const SPIConfig spi1config = { - 0, - /* HW dependent part.*/ - SSD1306_MISO_PORT, - SSD1306_MISO_PIN, - 0 - //SPI_CR1_BR_0 -}; - -#if GFX_USE_OS_CHIBIOS - static int32_t thdPriority = 0; -#endif +#define SPI_DRIVER (&SPID2) +#define SPI_PORT GPIOB +#define SCK_PAD 13 +#define MISO_PAD 14 +#define MOSI_PAD 15 + +#define CS_PORT GPIOC +#define RESET_PORT GPIOC +#define DNC_PORT GPIOC +#define CS_PAD 7 // 0 = chip selected +#define RESET_PAD 8 // 0 = reset +#define DNC_PAD 9 // control=0, data=1 + +static SPIConfig spi_cfg = { NULL, CS_PORT, CS_PAD, 0 }; static inline void init_board(GDisplay *g) { - unsigned i; - - // As we are not using multiple displays we set g->board to NULL as we don't use it. - g->board = 0; - - - switch(g->controllerdisplay) { - case 0: // Set up for Display 0 - // RESET pin. - palSetPadMode(SSD1306_RESET_PORT, SSD1306_RESET_PIN, PAL_MODE_OUTPUT_PUSHPULL); - - palSetPadMode(SSD1306_MISO_PORT, SSD1306_MISO_PIN, PAL_MODE_ALTERNATE(1)| - PAL_STM32_OSPEED_HIGHEST); - palSetPadMode(SSD1306_MOSI_PORT, SSD1306_MOSI_PIN, PAL_MODE_ALTERNATE(1)| - PAL_STM32_OSPEED_HIGHEST); - palSetPadMode(SSD1306_SCK_PORT, SSD1306_SCK_PIN, PAL_MODE_ALTERNATE(1)| - PAL_STM32_OSPEED_HIGHEST); - palSetPad(SSD1306_CS_PORT, SSD1306_CS_PIN); - palSetPadMode(SSD1306_CS_PORT, SSD1306_CS_PIN, PAL_MODE_ALTERNATE(1)| - PAL_STM32_OSPEED_HIGHEST); - spiInit(); - break; + (void) g; + g->board = 0; + // Maximum speed of SSD1306 is 10Mhz, so set SPI speed less or = to that. + // + // STM32 specific setup + // STM32_PCLK1 is APB1 frequence in hertz. + // STM32_PCLK2 is APB2 frequence in hertz. + // See manual clock diagram to determine APB1 or APB2 for spi in use. + // SPI2 uses APB1 clock on stm32151 + // BR bits divide PCLK as follows + // 000 /2 = 16 MHz + // 001 /4 = 8 MHz + // 010 /8 = 4 MHz + // 011 /16 = 2 MHz + // 100 /32 = 1 MHz + // 101 /64 = 500 kHz + // 110 /128 = 250 kHz + // 111 /256 = 125 kHz + unsigned long spi_clk = STM32_PCLK1 / 2; + unsigned code = 0; + while (spi_clk > 10000000) { + code++; + spi_clk /= 2; + } + spi_cfg.cr1 |= (code << 3); + + if (g->controllerdisplay == 0) { + palSetPadMode(SPI_PORT, SCK_PAD, PAL_MODE_ALTERNATE(5)|PAL_STM32_OTYPE_PUSHPULL|PAL_STM32_OSPEED_MID2); + palSetPadMode(SPI_PORT, MOSI_PAD, PAL_MODE_ALTERNATE(5)|PAL_STM32_OTYPE_PUSHPULL|PAL_STM32_OSPEED_MID2); + palSetPadMode(SPI_PORT, MISO_PAD, PAL_MODE_ALTERNATE(5)); + palSetPadMode(RESET_PORT, RESET_PAD, PAL_MODE_OUTPUT_PUSHPULL); + palSetPadMode(CS_PORT, CS_PAD, PAL_MODE_OUTPUT_PUSHPULL); + palSetPadMode(DNC_PORT, DNC_PAD, PAL_MODE_OUTPUT_PUSHPULL); + palSetPad(CS_PORT, CS_PAD); + palSetPad(RESET_PORT, RESET_PAD); + palClearPad(DNC_PORT, DNC_PAD); } } @@ -82,55 +77,39 @@ static inline void post_init_board(GDisplay *g) { (void) g; } + static inline void setpin_reset(GDisplay *g, bool_t state) { (void) g; - if(state) - CLR_RST - else - SET_RST + palWritePad(RESET_PORT, RESET_PAD, !state); } static inline void acquire_bus(GDisplay *g) { (void) g; - #if GFX_USE_OS_CHIBIOS - thdPriority = (int32_t)chThdGetPriority(); - chThdSetPriority(HIGHPRIO); - #endif - spiAcquireBus(&SPID1); + spiAcquireBus(SPI_DRIVER); + spiStart(SPI_DRIVER, &spi_cfg); + spiSelect(SPI_DRIVER); } static inline void release_bus(GDisplay *g) { (void) g; - #if GFX_USE_OS_CHIBIOS - chThdSetPriority(thdPriority); - #endif - spiReleaseBus(&SPID1); + spiUnselect(SPI_DRIVER); + spiStop(SPI_DRIVER); + spiReleaseBus(SPI_DRIVER); } static inline void write_cmd(GDisplay *g, uint8_t cmd) { - uint8_t command[2]; - (void) g; - - command[0] = 0x00; // Co = 0, D/C = 0 - command[1] = cmd; - - spiStart(&SPID1, &spi1config); - spiSelect(&SPID1); - spiStartSend(&SPID1, 2, command); - spiUnselect(&SPID1); - spiStop(&SPID1); + (void) g; + static uint8_t buf; + palClearPad(DNC_PORT, DNC_PAD); + buf = cmd; + spiSend(SPI_DRIVER, 1, &buf); } static inline void write_data(GDisplay *g, uint8_t* data, uint16_t length) { (void) g; - - spiStart(&SPID1, &spi1config); - spiSelect(&SPID1); - spiStartSend(&SPID1, length, data); - spiUnselect(&SPID1); - spiStop(&SPID1); + palSetPad(DNC_PORT, DNC_PAD); + spiSend(SPI_DRIVER, length, data); } #endif /* _GDISP_LLD_BOARD_H */ - -- cgit v1.2.3