mirror of
https://github.com/dougg3/mac-rom-simm-programmer.git
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7d0c5e2a09
It doesn't actually do anything yet, but it builds and runs. The next step will be to actually implement "fake" GPIO, USB, and parallel bus.
131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
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* spi.c
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*
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* Created on: Jul 17, 2021
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* Author: Doug
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*
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* Copyright (C) 2011-2021 Doug Brown
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (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, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#include "../spi.h"
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#include "gpio_hw.h"
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#include <stddef.h>
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/// The lone SPI controller available on this simulated PC build
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static SPIController controller =
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{
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.sckPin = {GPIOMISC, 1},
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.mosiPin = {GPIOMISC, 2},
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.misoPin = {GPIOMISC, 3}
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};
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/** Gets the SPI hardware controller at the specified index
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*
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* @param index The index of the controller. Only 0 is valid on this PC build.
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* @return The SPI controller, or NULL if an invalid index is supplied
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*/
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SPIController *SPI_Controller(uint8_t index)
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{
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// The simulated PC build only has one SPI controller
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return (index == 0) ? &controller : NULL;
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}
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/** Initializes the supplied SPI controller
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*
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* @param c The controller
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*/
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void SPI_InitController(SPIController *c)
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{
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GPIO_SetDirection(c->sckPin, true);
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GPIO_SetDirection(c->mosiPin, true);
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GPIO_SetDirection(c->misoPin, false);
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// Don't do anything with the rest of the registers.
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// SPI_RequestController will handle it.
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}
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/** Initializes the supplied SPI device
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*
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* @param spi The device
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* @param maxClock The maximum clock rate supported by the device in Hz
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* @param mode The SPI mode (see the SPI_MODE_*, SPI_CPHA, and SPI_CPOL defines)
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* @return True on success, false on failure
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*/
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bool SPI_InitDevice(SPIDevice *spi, uint32_t maxClock, uint8_t mode)
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{
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GPIO_SetDirection(spi->csPin, true);
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SPI_Deassert(spi);
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// TODO: Save the mode and clock?
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(void)maxClock; (void)mode;
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return true;
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}
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/** Allows an SPI device to request control of the bus.
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*
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* @param spi The SPI device
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*/
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void SPI_RequestBus(SPIDevice *spi)
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{
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(void)spi;
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}
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/** Allows an SPI device to relinquish control of the bus.
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*
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* @param spi The SPI device
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*/
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void SPI_ReleaseBus(SPIDevice *spi)
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{
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(void)spi;
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}
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/** Asserts an SPI device's chip select pin
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*
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* @param spi The SPI device
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*/
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void SPI_Assert(SPIDevice *spi)
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{
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GPIO_SetOff(spi->csPin);
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}
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/** Deasserts an SPI device's chip select pin
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*
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* @param spi The SPI device
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*/
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void SPI_Deassert(SPIDevice *spi)
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{
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GPIO_SetOn(spi->csPin);
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}
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/** Transfers a single byte to/from an SPI device
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*
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* @param spi The SPI device
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* @param b The byte to send
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* @return The byte that was simultaneously received
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*/
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uint8_t SPI_RWByte(SPIDevice *spi, uint8_t b)
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{
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// Since there's only one controller on this simulated PC, we don't actually care
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// about the SPI device pointer here
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(void)spi;
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// TODO: Do something with the byte, return the readback
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(void)b;
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return 0;
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}
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