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Diffstat (limited to 'nuttx/arch/arm/src/lpc313x/lpc313x_fdivinit.c')
-rwxr-xr-x | nuttx/arch/arm/src/lpc313x/lpc313x_fdivinit.c | 204 |
1 files changed, 0 insertions, 204 deletions
diff --git a/nuttx/arch/arm/src/lpc313x/lpc313x_fdivinit.c b/nuttx/arch/arm/src/lpc313x/lpc313x_fdivinit.c deleted file mode 100755 index 3d90bcba6..000000000 --- a/nuttx/arch/arm/src/lpc313x/lpc313x_fdivinit.c +++ /dev/null @@ -1,204 +0,0 @@ -/**************************************************************************** - * arch/arm/src/lpc313x/lpc313x_fdivinit.c - * - * Copyright (C) 2009 Gregory Nutt. All rights reserved. - * Author: Gregory Nutt <spudmonkey@racsa.co.cr> - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * 3. Neither the name NuttX nor the names of its contributors may be - * used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS - * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE - * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, - * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS - * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED - * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN - * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE - * POSSIBILITY OF SUCH DAMAGE. - * - ****************************************************************************/ - -/**************************************************************************** - * Included Files - ****************************************************************************/ - -#include <nuttx/config.h> - -#include <stdint.h> - -#include <arch/board/board.h> - -#include "lpc313x_cgu.h" -#include "lpc313x_cgudrvr.h" - -/**************************************************************************** - * Pre-processor Definitions - ****************************************************************************/ - -/**************************************************************************** - * Private Data - ****************************************************************************/ - -/**************************************************************************** - * Public Data - ****************************************************************************/ - -/**************************************************************************** - * Private Functions - ****************************************************************************/ - -/**************************************************************************** - * Name: lpc313x_bitwidth - * - * Description: - * Find the bit width of a msub or madd value. This will be use to - * extend the msub or madd values. To minimize power consumption, the - * lpc313x user manual recommends that madd and msub be shifted right - * to have as many trailing zero's as possible. This function detmines - * the pre-shifted with of one of the msub or madd values. - * - * EXAMPLE: - * - * Say an input frequency of 13 MHz is given while a frequency of 12 - * MHz is required. In this case we want a frequency - * - * f’ = 12/13 × f - * - * So n = 12 and m = 13. This then gives - * - * madd = m - n = 13 - 12 = 1 - * msub = -n = -12 - * - * In order to minimize power consumption madd and msub must be as - * large as possible. The limit of their values is determined by the - * madd/msub bit width. In this case msub is the largest value, - * in order to express -12, five bits are required. However since msub is - * always negative the fractional divider does not need the sign bit, leaving - * 4 bits. If madd/msub bit width has been set to say 8 bits, it is allowed - * to shift 4 bits, giving: - * - * msub’ = -(12<<4)= -12 × 24 = -12 × 16 = -192 - * madd’ = 1<<4 = 24 = 16 - * - ****************************************************************************/ - -static inline unsigned int -lpc313x_bitwidth(unsigned int value, unsigned int fdwid) -{ - unsigned int width = 0; - int bit; - - /* Examine bits from the most significant down */ - - for (bit = fdwid-1; bit >= 0; bit--) - { - /* Is this bit set? If so, then the width of the value is 0 to bit, - * or bit+1. - */ - - if ((value & (1 << bit)) != 0) - { - width = bit + 1; - break; - } - } - return width; -} - -/**************************************************************************** - * Public Functions - ****************************************************************************/ -/**************************************************************************** - * Name: lpc313x_fdivinit - * - * Description: - * Enable and configure (or disable) a fractional divider. - * - ****************************************************************************/ - -uint32_t lpc313x_fdivinit(int fdcndx, - const struct lpc313x_fdivconfig_s *fdiv, bool enable) -{ - uint32_t regaddr; - uint32_t regval; - unsigned int fdshift; - unsigned int fdwid; - unsigned int fdmask; - unsigned int maddshift; - unsigned int msubshift; - int madd; - int msub; - - /* Calculating the (unshifted) divider values.To minimize power - * consumption, the lpc313x user manual recommends that madd and msub - * be shifted right to have as many trailing zero's as possible. - */ - - madd = fdiv->m - fdiv->n; - msub = -fdiv->n; - - /* Determine the width of the madd and msub fields in the fractional divider - * register. They are all 8-bits in width except for fractional divider 17. - */ - - fdwid = CGU_FDC_FIELDWIDTH; - maddshift = CGU_FDC_MADD_SHIFT; - msubshift = CGU_FDC_MSUB_SHIFT; - - if (fdcndx == 17) - { - /* For fractional divider 17, the msub/madd field width is 13 */ - - fdwid = CGU_FDC17_FIELDWIDTH; - maddshift = CGU_FDC17_MADD_SHIFT; - msubshift = CGU_FDC17_MSUB_SHIFT; - } - - /* Find maximum bit width of madd & msub. Here we calculate the width of the OR - * of the two values. The width of the OR will be the width of the wider value - */ - - fdshift = fdwid - lpc313x_bitwidth((unsigned int)madd | (unsigned int)fdiv->n, fdwid); - - /* Calculate the fractional divider register values */ - - fdmask = (1 << fdwid) - 1; - madd = (madd << fdshift) & fdmask; - msub = (msub << fdshift) & fdmask; - regval = (madd << maddshift) | (msub << msubshift); - - /* Check if 50% duty cycle is needed for this divider */ - - if (fdiv->stretch) - { - regval |= CGU_FDC_STRETCH; - } - - /* Check if we should enable the divider immediately */ - - if (enable) - { - regval |= CGU_FDC_RUN; - } - - /* Finally configure the divider */ - - regaddr = LPC313X_CGU_FDC(fdcndx); - putreg32(regval, regaddr); - return regval; -} |