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git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5438 42af7a65-404d-4744-a932-0658087f49c3sbg
patacongo
12 years ago
19 changed files with 341 additions and 165 deletions
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/****************************************************************************
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* arch/z80/src/z180/z180_timerisr.c |
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* |
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* Copyright (C) 2012 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <gnutt@nuttx.org> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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****************************************************************************/ |
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/****************************************************************************
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* Included Files |
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****************************************************************************/ |
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#include <nuttx/config.h> |
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#include <stdint.h> |
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#include <time.h> |
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#include <debug.h> |
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#include <arch/board/board.h> |
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#include "clock_internal.h" |
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#include "up_internal.h" |
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#include "chip.h" |
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/****************************************************************************
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* Pre-processor Definitions |
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****************************************************************************/ |
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/* "The Z180 contains a two channel 16-bit Programmable Reload Timer. Each
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* PRT channel contains a 16-bit down counter and a 16-bit reload register." |
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* Channel 0 is dedicated as the system timer. |
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*/ |
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/* "The PRT input clock for both channels is equal to the system clock
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* divided by 20." |
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*/ |
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#define Z180_PRT_CLOCK (Z180_SYSCLOCK / 20) |
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/* The data Register "(TMDR) is decremented once every twenty clocks. When
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* TMDR counts down to 0, it is automatically reloaded with the value |
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* contained in the Reload Register (RLDR)." |
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*/ |
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#define A180_PRT0_RELOAD (Z180_PRT_CLOCK / CLK_TCK) |
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/****************************************************************************
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* Private Types |
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****************************************************************************/ |
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/****************************************************************************
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* Private Function Prototypes |
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****************************************************************************/ |
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/****************************************************************************
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* Global Functions |
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****************************************************************************/ |
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/****************************************************************************
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* Function: up_timerisr |
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* |
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* Description: |
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* The timer ISR will perform a variety of services for various portions |
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* of the systems. |
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* |
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****************************************************************************/ |
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int up_timerisr(int irq, chipreg_t *regs) |
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{ |
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volatile uint8_t regval; |
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/* "When TMDR0 decrements to 0, TIF0 is set to 1. This generates an interrupt
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* request if enabled by TIE0 = 1. TIF0 is reset to 0 when TCR is read and |
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* the higher or lower byte of TMDR0 is read." |
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*/ |
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regval = inp(Z180_PRT_TCR); |
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regval = inp(Z180_PRT0_DRL); |
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regval = inp(Z180_PRT0_DRH); |
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/* Process timer interrupt */ |
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sched_process_timer(); |
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return 0; |
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} |
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/****************************************************************************
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* Function: up_timerinit |
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* |
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* Description: |
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* This function is called during start-up to initialize the timer |
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* interrupt. |
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* |
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****************************************************************************/ |
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void up_timerinit(void) |
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{ |
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uint8_t regval; |
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/* Configure PRT0 to interrupt at the requested rate */ |
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/* First stop PRT0 and disable interrupts */ |
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regval = inp(Z180_PRT_TCR); |
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regval &= (PRT_TCR_TIF0|PRT_TCR_TIE0|PRT_TCR_TDE0); |
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outp(Z180_PRT_TCR, regval); |
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/* Set the timer reload value so that the timer will interrupt at the
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* desired frequency. "For writing, the TMDR down counting must be |
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* inhibited using the TDE (Timer Down Count Enable) bits in the TCR |
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* (Timer Control Register). Then, any or both higher and lower bytes of |
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* TMDR can be freely written (and read) in any order." |
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*/ |
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outp(Z180_PRT0_RLDRL, (A180_PRT0_RELOAD & 0xff)); |
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outp(Z180_PRT0_RLDRH, (A180_PRT0_RELOAD >> 8)); |
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/* Enable down-counting */ |
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regval |= PRT_TCR_TDE0; |
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outp(Z180_PRT_TCR, regval); |
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/* Attach the timer interrupt vector */ |
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(void)irq_attach(Z180_PRT0, (xcpt_t)up_timerisr); |
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/* And enable the timer interrupt */ |
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regval |= PRT_TCR_TIE0; |
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outp(Z180_PRT_TCR, regval); |
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} |
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