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https://github.com/dougg3/mac-rom-simm-programmer.git
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9476de85b4
If it gets this far, the firmware is at least sort of running, so the watchdog has served its purpose of resetting to the bootloader if there's invalid firmware flashed to the device.
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
/*
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* board.c
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*
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* Created on: Jun 19, 2023
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* Author: Doug
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*
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* Copyright (C) 2011-2023 Doug Brown
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*
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*/
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#include "board_hw.h"
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/** Initializes any board hardware-specific stuff
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*
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*/
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void Board_Init(void)
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{
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// Unlock protected registers so we can configure clocks, flash, WDT, etc.
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do
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{
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SYS->REGLCTL = 0x59UL;
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SYS->REGLCTL = 0x16UL;
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SYS->REGLCTL = 0x88UL;
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} while (SYS->REGLCTL == 0UL);
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// Enable 48 MHz internal high-speed RC oscillator
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CLK->PWRCTL |= CLK_PWRCTL_HIRCEN_Msk;
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// Wait until it's ready
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while (!(CLK->STATUS & CLK_STATUS_HIRCSTB_Msk));
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// Clock HCLK and USB from 48 MHz HIRC
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CLK->CLKSEL0 = (CLK->CLKSEL0 & (~(CLK_CLKSEL0_HCLKSEL_Msk | CLK_CLKSEL0_USBDSEL_Msk))) |
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(7 << CLK_CLKSEL0_HCLKSEL_Pos) | (0 << CLK_CLKSEL0_USBDSEL_Pos);
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// SystemCoreClock, CyclesPerUs, CyclesPerUs default to correct values already
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// Enable USB device controller
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CLK->APBCLK0 |= CLK_APBCLK0_USBDCKEN_Msk;
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// Enable timer 0
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CLK->APBCLK0 |= CLK_APBCLK0_TMR0CKEN_Msk;
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// Timer 0 clock source = 48 MHz HIRC
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CLK->CLKSEL1 = (CLK->CLKSEL1 & (~(CLK_CLKSEL1_TMR0SEL_Msk))) | (7UL << CLK_CLKSEL1_TMR0SEL_Pos);
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// Enable all GPIO
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CLK->AHBCLK |=
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CLK_AHBCLK_GPACKEN_Msk |
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CLK_AHBCLK_GPBCKEN_Msk |
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CLK_AHBCLK_GPCCKEN_Msk |
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CLK_AHBCLK_GPDCKEN_Msk |
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CLK_AHBCLK_GPECKEN_Msk |
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CLK_AHBCLK_GPFCKEN_Msk;
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// Start the timer, prescaler = 48, so 1 MHz
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TIMER0->CTL = TIMER_CTL_CNTEN_Msk | (3UL << TIMER_CTL_OPMODE_Pos) | 47;
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// Disable WDT now; the main firmware is booted.
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WDT->CTL = (6 << WDT_CTL_TOUTSEL_Pos);
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}
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/** Determines if a brownout was detected at startup
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*
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* @return True if a brownout was detected
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*/
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bool Board_BrownoutDetected(void)
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{
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return false;
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}
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