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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [CORTEX_LM3S811_KEIL/] [LuminaryCode/] [osram96x16.c] - Rev 596
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//***************************************************************************** // // osram96x16.c - Driver for the OSRAM 96x16 graphical OLED display. // // Copyright (c) 2006 Luminary Micro, Inc. All rights reserved. // // Software License Agreement // // Luminary Micro, Inc. (LMI) is supplying this software for use solely and // exclusively on LMI's Stellaris Family of microcontroller products. // // The software is owned by LMI and/or its suppliers, and is protected under // applicable copyright laws. All rights are reserved. Any use in violation // of the foregoing restrictions may subject the user to criminal sanctions // under applicable laws, as well as to civil liability for the breach of the // terms and conditions of this license. // // THIS SOFTWARE IS PROVIDED "AS IS". NO WARRANTIES, WHETHER EXPRESS, IMPLIED // OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. // LMI SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR // CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER. // // This is part of revision 816 of the Stellaris Driver Library. // //***************************************************************************** //***************************************************************************** // //! \addtogroup ev_lm3s811_api //! @{ // //***************************************************************************** #include "hw_i2c.h" #include "hw_memmap.h" #include "hw_sysctl.h" #include "hw_types.h" #include "src/debug.h" #include "src/gpio.h" #include "src/i2c.h" #include "src/sysctl.h" #include "osram96x16.h" extern void I2CMasterInitExpClk(unsigned long ulBase, unsigned long ulI2CClk, tBoolean bFast); //***************************************************************************** // // The I2C slave address of the SSD0303 controller on the OLED display. // //***************************************************************************** #define SSD0303_ADDR 0x3d //***************************************************************************** // // A 5x7 font (in a 6x8 cell, where the sixth column is omitted from this // table) for displaying text on the OLED display. The data is organized as // bytes from the left column to the right column, with each byte containing // the top row in the LSB and the bottom row in the MSB. // //***************************************************************************** static const unsigned char g_pucFont[95][5] = { { 0x00, 0x00, 0x00, 0x00, 0x00 }, // " " { 0x00, 0x00, 0x4f, 0x00, 0x00 }, // ! { 0x00, 0x07, 0x00, 0x07, 0x00 }, // " { 0x14, 0x7f, 0x14, 0x7f, 0x14 }, // # { 0x24, 0x2a, 0x7f, 0x2a, 0x12 }, // $ { 0x23, 0x13, 0x08, 0x64, 0x62 }, // % { 0x36, 0x49, 0x55, 0x22, 0x50 }, // & { 0x00, 0x05, 0x03, 0x00, 0x00 }, // ' { 0x00, 0x1c, 0x22, 0x41, 0x00 }, // ( { 0x00, 0x41, 0x22, 0x1c, 0x00 }, // ) { 0x14, 0x08, 0x3e, 0x08, 0x14 }, // * { 0x08, 0x08, 0x3e, 0x08, 0x08 }, // + { 0x00, 0x50, 0x30, 0x00, 0x00 }, // , { 0x08, 0x08, 0x08, 0x08, 0x08 }, // - { 0x00, 0x60, 0x60, 0x00, 0x00 }, // . { 0x20, 0x10, 0x08, 0x04, 0x02 }, // / { 0x3e, 0x51, 0x49, 0x45, 0x3e }, // 0 { 0x00, 0x42, 0x7f, 0x40, 0x00 }, // 1 { 0x42, 0x61, 0x51, 0x49, 0x46 }, // 2 { 0x21, 0x41, 0x45, 0x4b, 0x31 }, // 3 { 0x18, 0x14, 0x12, 0x7f, 0x10 }, // 4 { 0x27, 0x45, 0x45, 0x45, 0x39 }, // 5 { 0x3c, 0x4a, 0x49, 0x49, 0x30 }, // 6 { 0x01, 0x71, 0x09, 0x05, 0x03 }, // 7 { 0x36, 0x49, 0x49, 0x49, 0x36 }, // 8 { 0x06, 0x49, 0x49, 0x29, 0x1e }, // 9 { 0x00, 0x36, 0x36, 0x00, 0x00 }, // : { 0x00, 0x56, 0x36, 0x00, 0x00 }, // ; { 0x08, 0x14, 0x22, 0x41, 0x00 }, // < { 0x14, 0x14, 0x14, 0x14, 0x14 }, // = { 0x00, 0x41, 0x22, 0x14, 0x08 }, // > { 0x02, 0x01, 0x51, 0x09, 0x06 }, // ? { 0x32, 0x49, 0x79, 0x41, 0x3e }, // @ { 0x7e, 0x11, 0x11, 0x11, 0x7e }, // A { 0x7f, 0x49, 0x49, 0x49, 0x36 }, // B { 0x3e, 0x41, 0x41, 0x41, 0x22 }, // C { 0x7f, 0x41, 0x41, 0x22, 0x1c }, // D { 0x7f, 0x49, 0x49, 0x49, 0x41 }, // E { 0x7f, 0x09, 0x09, 0x09, 0x01 }, // F { 0x3e, 0x41, 0x49, 0x49, 0x7a }, // G { 0x7f, 0x08, 0x08, 0x08, 0x7f }, // H { 0x00, 0x41, 0x7f, 0x41, 0x00 }, // I { 0x20, 0x40, 0x41, 0x3f, 0x01 }, // J { 0x7f, 0x08, 0x14, 0x22, 0x41 }, // K { 0x7f, 0x40, 0x40, 0x40, 0x40 }, // L { 0x7f, 0x02, 0x0c, 0x02, 0x7f }, // M { 0x7f, 0x04, 0x08, 0x10, 0x7f }, // N { 0x3e, 0x41, 0x41, 0x41, 0x3e }, // O { 0x7f, 0x09, 0x09, 0x09, 0x06 }, // P { 0x3e, 0x41, 0x51, 0x21, 0x5e }, // Q { 0x7f, 0x09, 0x19, 0x29, 0x46 }, // R { 0x46, 0x49, 0x49, 0x49, 0x31 }, // S { 0x01, 0x01, 0x7f, 0x01, 0x01 }, // T { 0x3f, 0x40, 0x40, 0x40, 0x3f }, // U { 0x1f, 0x20, 0x40, 0x20, 0x1f }, // V { 0x3f, 0x40, 0x38, 0x40, 0x3f }, // W { 0x63, 0x14, 0x08, 0x14, 0x63 }, // X { 0x07, 0x08, 0x70, 0x08, 0x07 }, // Y { 0x61, 0x51, 0x49, 0x45, 0x43 }, // Z { 0x00, 0x7f, 0x41, 0x41, 0x00 }, // [ { 0x02, 0x04, 0x08, 0x10, 0x20 }, // "\" { 0x00, 0x41, 0x41, 0x7f, 0x00 }, // ] { 0x04, 0x02, 0x01, 0x02, 0x04 }, // ^ { 0x40, 0x40, 0x40, 0x40, 0x40 }, // _ { 0x00, 0x01, 0x02, 0x04, 0x00 }, // ` { 0x20, 0x54, 0x54, 0x54, 0x78 }, // a { 0x7f, 0x48, 0x44, 0x44, 0x38 }, // b { 0x38, 0x44, 0x44, 0x44, 0x20 }, // c { 0x38, 0x44, 0x44, 0x48, 0x7f }, // d { 0x38, 0x54, 0x54, 0x54, 0x18 }, // e { 0x08, 0x7e, 0x09, 0x01, 0x02 }, // f { 0x0c, 0x52, 0x52, 0x52, 0x3e }, // g { 0x7f, 0x08, 0x04, 0x04, 0x78 }, // h { 0x00, 0x44, 0x7d, 0x40, 0x00 }, // i { 0x20, 0x40, 0x44, 0x3d, 0x00 }, // j { 0x7f, 0x10, 0x28, 0x44, 0x00 }, // k { 0x00, 0x41, 0x7f, 0x40, 0x00 }, // l { 0x7c, 0x04, 0x18, 0x04, 0x78 }, // m { 0x7c, 0x08, 0x04, 0x04, 0x78 }, // n { 0x38, 0x44, 0x44, 0x44, 0x38 }, // o { 0x7c, 0x14, 0x14, 0x14, 0x08 }, // p { 0x08, 0x14, 0x14, 0x18, 0x7c }, // q { 0x7c, 0x08, 0x04, 0x04, 0x08 }, // r { 0x48, 0x54, 0x54, 0x54, 0x20 }, // s { 0x04, 0x3f, 0x44, 0x40, 0x20 }, // t { 0x3c, 0x40, 0x40, 0x20, 0x7c }, // u { 0x1c, 0x20, 0x40, 0x20, 0x1c }, // v { 0x3c, 0x40, 0x30, 0x40, 0x3c }, // w { 0x44, 0x28, 0x10, 0x28, 0x44 }, // x { 0x0c, 0x50, 0x50, 0x50, 0x3c }, // y { 0x44, 0x64, 0x54, 0x4c, 0x44 }, // z { 0x00, 0x08, 0x36, 0x41, 0x00 }, // { { 0x00, 0x00, 0x7f, 0x00, 0x00 }, // | { 0x00, 0x41, 0x36, 0x08, 0x00 }, // } { 0x02, 0x01, 0x02, 0x04, 0x02 }, // ~ }; //***************************************************************************** // // The sequence of commands used to initialize the SSD0303 controller. Each // command is described as follows: there is a byte specifying the number of // bytes in the I2C transfer, followed by that many bytes of command data. // //***************************************************************************** static const unsigned char g_pucOSRAMInit[] = { // // Turn off the panel // 0x02, 0x80, 0xae, // // Set lower column address // 0x02, 0x80, 0x04, // // Set higher column address // 0x02, 0x80, 0x12, // // Set contrast control register // 0x04, 0x80, 0x81, 0x80, 0x2b, // // Set segment re-map // 0x02, 0x80, 0xa1, // // Set display start line // 0x02, 0x80, 0x40, // // Set display offset // 0x04, 0x80, 0xd3, 0x80, 0x00, // // Set multiplex ratio // 0x04, 0x80, 0xa8, 0x80, 0x0f, // // Set the display to normal mode // 0x02, 0x80, 0xa4, // // Non-inverted display // 0x02, 0x80, 0xa6, // // Set the page address // 0x02, 0x80, 0xb0, // // Set COM output scan direction // 0x02, 0x80, 0xc8, // // Set display clock divide ratio/oscillator frequency // 0x04, 0x80, 0xd5, 0x80, 0x72, // // Enable mono mode // 0x04, 0x80, 0xd8, 0x80, 0x00, // // Set pre-charge period // 0x04, 0x80, 0xd9, 0x80, 0x22, // // Set COM pins hardware configuration // 0x04, 0x80, 0xda, 0x80, 0x12, // // Set VCOM deslect level // 0x04, 0x80, 0xdb, 0x80, 0x0f, // // Set DC-DC on // 0x04, 0x80, 0xad, 0x80, 0x8b, // // Turn on the panel // 0x02, 0x80, 0xaf, }; //***************************************************************************** // // The inter-byte delay required by the SSD0303 OLED controller. // //***************************************************************************** static unsigned long g_ulDelay; //***************************************************************************** // //! \internal //! //! Provide a small delay. //! //! \param ulCount is the number of delay loop iterations to perform. //! //! Since the SSD0303 controller needs a delay between bytes written to it over //! the I2C bus, this function provides a means of generating that delay. It //! is written in assembly to keep the delay consistent across tool chains, //! avoiding the need to tune the delay based on the tool chain in use. //! //! \return None. // //***************************************************************************** #if defined(ewarm) static void OSRAMDelay(unsigned long ulCount) { __asm(" subs r0, #1\n" " bne OSRAMDelay\n" " bx lr"); } #endif #if defined(gcc) static void __attribute__((naked)) OSRAMDelay(unsigned long ulCount) { __asm(" subs r0, #1\n" " bne OSRAMDelay\n" " bx lr"); } #endif #if defined(rvmdk) || defined(__ARMCC_VERSION) __asm void OSRAMDelay(unsigned long ulCount) { subs r0, #1; bne OSRAMDelay; bx lr; } #endif //***************************************************************************** // //! \internal //! //! Start a transfer to the SSD0303 controller. //! //! \param ucChar is the first byte to be written to the controller. //! //! This function will start a transfer to the SSD0303 controller via the I2C //! bus. //! //! The data is written in a polled fashion; this function will not return //! until the byte has been written to the controller. //! //! \return None. // //***************************************************************************** static void OSRAMWriteFirst(unsigned char ucChar) { // // Set the slave address. // I2CMasterSlaveAddrSet(I2C_MASTER_BASE, SSD0303_ADDR, false); // // Write the first byte to the controller. // I2CMasterDataPut(I2C_MASTER_BASE, ucChar); // // Start the transfer. // I2CMasterControl(I2C_MASTER_BASE, I2C_MASTER_CMD_BURST_SEND_START); } //***************************************************************************** // //! \internal //! //! Write a byte to the SSD0303 controller. //! //! \param ucChar is the byte to be transmitted to the controller. //! //! This function continues a transfer to the SSD0303 controller by writing //! another byte over the I2C bus. This must only be called after calling //! OSRAMWriteFirst(), but before calling OSRAMWriteFinal(). //! //! The data is written in a polled faashion; this function will not return //! until the byte has been written to the controller. //! //! \return None. // //***************************************************************************** static void OSRAMWriteByte(unsigned char ucChar) { // // Wait until the current byte has been transferred. // while(I2CMasterIntStatus(I2C_MASTER_BASE, false) == 0) { } // // Provide the required inter-byte delay. // OSRAMDelay(g_ulDelay); // // Write the next byte to the controller. // I2CMasterDataPut(I2C_MASTER_BASE, ucChar); // // Continue the transfer. // I2CMasterControl(I2C_MASTER_BASE, I2C_MASTER_CMD_BURST_SEND_CONT); } //***************************************************************************** // //! \internal //! //! Write a sequence of bytes to the SSD0303 controller. //! //! This function continues a transfer to the SSD0303 controller by writing a //! sequence of bytes over the I2C bus. This must only be called after calling //! OSRAMWriteFirst(), but before calling OSRAMWriteFinal(). //! //! The data is written in a polled fashion; this function will not return //! until the entire byte sequence has been written to the controller. //! //! \return None. // //***************************************************************************** static void OSRAMWriteArray(const unsigned char *pucBuffer, unsigned long ulCount) { // // Loop while there are more bytes left to be transferred. // while(ulCount != 0) { // // Wait until the current byte has been transferred. // while(I2CMasterIntStatus(I2C_MASTER_BASE, false) == 0) { } // // Provide the required inter-byte delay. // OSRAMDelay(g_ulDelay); // // Write the next byte to the controller. // I2CMasterDataPut(I2C_MASTER_BASE, *pucBuffer++); ulCount--; // // Continue the transfer. // I2CMasterControl(I2C_MASTER_BASE, I2C_MASTER_CMD_BURST_SEND_CONT); } } //***************************************************************************** // //! \internal //! //! Finish a transfer to the SSD0303 controller. //! //! \param ucChar is the final byte to be written to the controller. //! //! This function will finish a transfer to the SSD0303 controller via the I2C //! bus. This must only be called after calling OSRAMWriteFirst(). //! //! The data is written in a polled fashion; this function will not return //! until the byte has been written to the controller. //! //! \return None. // //***************************************************************************** static void OSRAMWriteFinal(unsigned char ucChar) { // // Wait until the current byte has been transferred. // while(I2CMasterIntStatus(I2C_MASTER_BASE, false) == 0) { } // // Provide the required inter-byte delay. // OSRAMDelay(g_ulDelay); // // Write the final byte to the controller. // I2CMasterDataPut(I2C_MASTER_BASE, ucChar); // // Finish the transfer. // I2CMasterControl(I2C_MASTER_BASE, I2C_MASTER_CMD_BURST_SEND_FINISH); // // Wait until the final byte has been transferred. // while(I2CMasterIntStatus(I2C_MASTER_BASE, false) == 0) { } // // Provide the required inter-byte delay. // OSRAMDelay(g_ulDelay); } //***************************************************************************** // //! Clears the OLED display. //! //! This function will clear the display. All pixels in the display will be //! turned off. //! //! \return None. // //***************************************************************************** void OSRAMClear(void) { static const unsigned char pucRow1[] = { 0xb0, 0x80, 0x04, 0x80, 0x12, 0x40 }; static const unsigned char pucRow2[] = { 0xb1, 0x80, 0x04, 0x80, 0x12, 0x40 }; unsigned long ulIdx; // // Move the display cursor to the first column of the first row. // OSRAMWriteFirst(0x80); OSRAMWriteArray(pucRow1, sizeof(pucRow1)); // // Fill this row with zeros. // for(ulIdx = 0; ulIdx < 95; ulIdx++) { OSRAMWriteByte(0x00); } OSRAMWriteFinal(0x00); // // Move the display cursor to the first column of the second row. // OSRAMWriteFirst(0x80); OSRAMWriteArray(pucRow2, sizeof(pucRow2)); // // Fill this row with zeros. // for(ulIdx = 0; ulIdx < 95; ulIdx++) { OSRAMWriteByte(0x00); } OSRAMWriteFinal(0x00); } //***************************************************************************** // //! Displays a string on the OLED display. //! //! \param pcStr is a pointer to the string to display. //! \param ulX is the horizontal position to display the string, specified in //! columns from the left edge of the display. //! \param ulY is the vertical position to display the string, specified in //! eight scan line blocks from the top of the display (i.e. only 0 and 1 are //! valid). //! //! This function will draw a string on the display. Only the ASCII characters //! between 32 (space) and 126 (tilde) are supported; other characters will //! result in random data being draw on the display (based on whatever appears //! before/after the font in memory). The font is mono-spaced, so characters //! such as "i" and "l" have more white space around them than characters such //! as "m" or "w". //! //! If the drawing of the string reaches the right edge of the display, no more //! characters will be drawn. Therefore, special care is not required to avoid //! supplying a string that is "too long" to display. //! //! \return None. // //***************************************************************************** void OSRAMStringDraw(const char *pcStr, unsigned long ulX, unsigned long ulY) { // // Check the arguments. // ASSERT(ulX < 96); ASSERT(ulY < 2); // // Move the display cursor to the requested position on the display. // OSRAMWriteFirst(0x80); OSRAMWriteByte((ulY == 0) ? 0xb0 : 0xb1); OSRAMWriteByte(0x80); OSRAMWriteByte((ulX + 36) & 0x0f); OSRAMWriteByte(0x80); OSRAMWriteByte(0x10 | (((ulX + 36) >> 4) & 0x0f)); OSRAMWriteByte(0x40); // // Loop while there are more characters in the string. // while(*pcStr != 0) { // // See if there is enough space on the display for this entire // character. // if(ulX <= 90) { // // Write the contents of this character to the display. // OSRAMWriteArray(g_pucFont[*pcStr - ' '], 5); // // See if this is the last character to display (either because the // right edge has been reached or because there are no more // characters). // if((ulX == 90) || (pcStr[1] == 0)) { // // Write the final column of the display. // OSRAMWriteFinal(0x00); // // The string has been displayed. // return; } // // Write the inter-character padding column. // OSRAMWriteByte(0x00); } else { // // Write the portion of the character that will fit onto the // display. // OSRAMWriteArray(g_pucFont[*pcStr - ' '], 95 - ulX); OSRAMWriteFinal(g_pucFont[*pcStr - ' '][95 - ulX]); // // The string has been displayed. // return; } // // Advance to the next character. // pcStr++; // // Increment the X coordinate by the six columns that were just // written. // ulX += 6; } } //***************************************************************************** // //! Displays an image on the OLED display. //! //! \param pucImage is a pointer to the image data. //! \param ulX is the horizontal position to display this image, specified in //! columns from the left edge of the display. //! \param ulY is the vertical position to display this image, specified in //! eight scan line blocks from the top of the display (i.e. only 0 and 1 are //! valid). //! \param ulWidth is the width of the image, specified in columns. //! \param ulHeight is the height of the image, specified in eight row blocks //! (i.e. only 1 and 2 are valid). //! //! This function will display a bitmap graphic on the display. The image to //! be displayed must be a multiple of eight scan lines high (i.e. one row) and //! will be drawn at a vertical position that is a multiple of eight scan lines //! (i.e. scan line zero or scan line eight, corresponding to row zero or row //! one). //! //! The image data is organized with the first row of image data appearing left //! to right, followed immediately by the second row of image data. Each byte //! contains the data for the eight scan lines of the column, with the top scan //! line being in the least significant bit of the byte and the bottom scan //! line being in the most significant bit of the byte. //! //! For example, an image four columns wide and sixteen scan lines tall would //! be arranged as follows (showing how the eight bytes of the image would //! appear on the display): //! //! \verbatim //! +-------+ +-------+ +-------+ +-------+ //! | | 0 | | | 0 | | | 0 | | | 0 | //! | B | 1 | | B | 1 | | B | 1 | | B | 1 | //! | y | 2 | | y | 2 | | y | 2 | | y | 2 | //! | t | 3 | | t | 3 | | t | 3 | | t | 3 | //! | e | 4 | | e | 4 | | e | 4 | | e | 4 | //! | | 5 | | | 5 | | | 5 | | | 5 | //! | 0 | 6 | | 1 | 6 | | 2 | 6 | | 3 | 6 | //! | | 7 | | | 7 | | | 7 | | | 7 | //! +-------+ +-------+ +-------+ +-------+ //! //! +-------+ +-------+ +-------+ +-------+ //! | | 0 | | | 0 | | | 0 | | | 0 | //! | B | 1 | | B | 1 | | B | 1 | | B | 1 | //! | y | 2 | | y | 2 | | y | 2 | | y | 2 | //! | t | 3 | | t | 3 | | t | 3 | | t | 3 | //! | e | 4 | | e | 4 | | e | 4 | | e | 4 | //! | | 5 | | | 5 | | | 5 | | | 5 | //! | 4 | 6 | | 5 | 6 | | 6 | 6 | | 7 | 6 | //! | | 7 | | | 7 | | | 7 | | | 7 | //! +-------+ +-------+ +-------+ +-------+ //! \endverbatim //! //! \return None. // //***************************************************************************** void OSRAMImageDraw(const unsigned char *pucImage, unsigned long ulX, unsigned long ulY, unsigned long ulWidth, unsigned long ulHeight) { // // Check the arguments. // ASSERT(ulX < 96); ASSERT(ulY < 2); ASSERT((ulX + ulWidth) <= 96); ASSERT((ulY + ulHeight) <= 2); // // The first 36 columns of the LCD buffer are not displayed, so increment // the X coorddinate by 36 to account for the non-displayed frame buffer // memory. // ulX += 36; // // Loop while there are more rows to display. // while(ulHeight--) { // // Write the starting address within this row. // OSRAMWriteFirst(0x80); OSRAMWriteByte((ulY == 0) ? 0xb0 : 0xb1); OSRAMWriteByte(0x80); OSRAMWriteByte(ulX & 0x0f); OSRAMWriteByte(0x80); OSRAMWriteByte(0x10 | ((ulX >> 4) & 0x0f)); OSRAMWriteByte(0x40); // // Write this row of image data. // OSRAMWriteArray(pucImage, ulWidth - 1); OSRAMWriteFinal(pucImage[ulWidth - 1]); // // Advance to the next row of the image. // pucImage += ulWidth; ulY++; } } //***************************************************************************** // //! Initialize the OLED display. //! //! \param bFast is a boolean that is \e true if the I2C interface should be //! run at 400 kbps and \e false if it should be run at 100 kbps. //! //! This function initializes the I2C interface to the OLED display and //! configures the SSD0303 controller on the panel. //! //! \return None. // //***************************************************************************** void OSRAMInit(tBoolean bFast) { unsigned long ulIdx; // // Enable the I2C and GPIO port B blocks as they are needed by this driver. // SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C); SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB); // // Configure the I2C SCL and SDA pins for I2C operation. // GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_2 | GPIO_PIN_3); // // Initialize the I2C master. // I2CMasterInitExpClk(I2C_MASTER_BASE, SysCtlClockGet(), bFast); // // Compute the inter-byte delay for the SSD0303 controller. This delay is // dependent upon the I2C bus clock rate; the slower the clock the longer // the delay required. // // The derivation of this formula is based on a measured delay of // OSRAMDelay(1700) for a 100 kHz I2C bus with the CPU running at 50 MHz // (referred to as C). To scale this to the delay for a different CPU // speed (since this is just a CPU-based delay loop) is: // // f(CPU) // C * ---------- // 50,000,000 // // To then scale this to the actual I2C rate (since it won't always be // precisely 100 kHz): // // f(CPU) 100,000 // C * ---------- * ------- // 50,000,000 f(I2C) // // This equation will give the inter-byte delay required for any // configuration of the I2C master. But, as arranged it is impossible to // directly compute in 32-bit arithmetic (without loosing a lot of // accuracy). So, the equation is simplified. // // Since f(I2C) is generated by dividing down from f(CPU), replace it with // the equivalent (where TPR is the value programmed into the Master Timer // Period Register of the I2C master, with the 1 added back): // // 100,000 // f(CPU) ------- // C * ---------- * f(CPU) // 50,000,000 ------------ // 2 * 10 * TPR // // Inverting the dividend in the last term: // // f(CPU) 100,000 * 2 * 10 * TPR // C * ---------- * ---------------------- // 50,000,000 f(CPU) // // The f(CPU) now cancels out. // // 100,000 * 2 * 10 * TPR // C * ---------------------- // 50,000,000 // // Since there are no clock frequencies left in the equation, this equation // also works for 400 kHz bus operation as well, since the 100,000 in the // numerator becomes 400,000 but C is 1/4, which cancel out each other. // Reducing the constants gives: // // TPR TPR TPR // C * --- = 1700 * --- = 340 * --- // 25 25 5 // // Note that the constant C is actually a bit larger than it needs to be in // order to provide some safety margin. // // When the panel is being initialized, the value of C actually needs to be // a bit longer (3200 instead of 1700). So, set the larger value for now. // g_ulDelay = (640 * (HWREG(I2C_MASTER_BASE + I2C_MASTER_O_TPR) + 1)) / 5; // // Initialize the SSD0303 controller. Loop through the initialization // sequence doing a single I2C transfer for each command. // for(ulIdx = 0; ulIdx < sizeof(g_pucOSRAMInit); ulIdx += g_pucOSRAMInit[ulIdx] + 1) { // // Send this command. // OSRAMWriteFirst(g_pucOSRAMInit[ulIdx + 1]); OSRAMWriteArray(g_pucOSRAMInit + ulIdx + 2, g_pucOSRAMInit[ulIdx] - 2); OSRAMWriteFinal(g_pucOSRAMInit[ulIdx + g_pucOSRAMInit[ulIdx]]); } // // Now, switch to the actual value of C. // g_ulDelay = (340 * (HWREG(I2C_MASTER_BASE + I2C_MASTER_O_TPR) + 1)) / 5; // // Clear the frame buffer. // OSRAMClear(); } //***************************************************************************** // //! Turns on the OLED display. //! //! This function will turn on the OLED display, causing it to display the //! contents of its internal frame buffer. //! //! \return None. // //***************************************************************************** void OSRAMDisplayOn(void) { // // Turn on the DC-DC converter and the display. // OSRAMWriteFirst(0x80); OSRAMWriteByte(0xad); OSRAMWriteByte(0x80); OSRAMWriteByte(0x8b); OSRAMWriteByte(0x80); OSRAMWriteFinal(0xaf); } //***************************************************************************** // //! Turns off the OLED display. //! //! This function will turn off the OLED display. This will stop the scanning //! of the panel and turn off the on-chip DC-DC converter, preventing damage to //! the panel due to burn-in (it has similar characters to a CRT in this //! respect). //! //! \return None. // //***************************************************************************** void OSRAMDisplayOff(void) { // // Turn off the DC-DC converter and the display. // OSRAMWriteFirst(0x80); OSRAMWriteByte(0xad); OSRAMWriteByte(0x80); OSRAMWriteByte(0x8a); OSRAMWriteByte(0x80); OSRAMWriteFinal(0xae); } //***************************************************************************** // // Close the Doxygen group. //! @} // //*****************************************************************************
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