Macintosh-SW/mac-rom-simm-programmer
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mac-rom-simm-programmer/hal/spi.h

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Break out code into a HAL, optimize flash operations This makes the code pretty easily portable to other architectures if someone wants to make a more modern SIMM programmer. I also was pretty careful to split responsibilities of the different components and give the existing components better names. I'm pretty happy with the organization of the code now. As part of this change I have also heavily optimized the code. In particular, the read and write cycle routines are very important to the overall performance of the programmer. In these routines I had to make some tradeoffs of code performance versus prettiness, but the overall result is much faster programming. Some of these performance changes are the result of what I discovered when I upgraded my AVR compiler. I discovered that it is smarter at looking at 32-bit variables when I use a union instead of bitwise operations. I also shaved off more CPU cycles by carefully making a few small tweaks. I added a bypass for the "program only some chips" mask, because it was adding unnecessary CPU cycles for a feature that is rarely used. I removed the verification feature from the write routine, because we can always verify the data after the write chunk is complete, which is more efficient. I also added assumptions about the initial/final state of the CS/OE/WE pins, which allowed me to remove more valuable CPU cycles from the read/write cycle routines. There are also a few enormous performance optimizations I should have done a long time ago: 1) The code was only handling one received byte per main loop iteration. Reading every byte available cut nearly a minute off of the 8 MB programming time. 2) The code wasn't taking advantage of the faster programming command available in the chips used on the 8 MB SIMM. The end result of all of these optimizations is I have programming time of the 8 MB SIMM down to 3:31 (it used to be 8:43). Another minor issue I fixed: the Micron SIMM chip identification wasn't working properly. It was outputting the manufacturer ID again instead of the device ID.
2020-11-18 05:03:32 +00:00
/*
* spi.h
*
* Created on: Nov 14, 2020
* Author: Doug
Add/update copyright This just makes sure everything is up to date with copyrights.
2020-11-23 06:28:47 +00:00
*
* Copyright (C) 2011-2020 Doug Brown
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
Break out code into a HAL, optimize flash operations This makes the code pretty easily portable to other architectures if someone wants to make a more modern SIMM programmer. I also was pretty careful to split responsibilities of the different components and give the existing components better names. I'm pretty happy with the organization of the code now. As part of this change I have also heavily optimized the code. In particular, the read and write cycle routines are very important to the overall performance of the programmer. In these routines I had to make some tradeoffs of code performance versus prettiness, but the overall result is much faster programming. Some of these performance changes are the result of what I discovered when I upgraded my AVR compiler. I discovered that it is smarter at looking at 32-bit variables when I use a union instead of bitwise operations. I also shaved off more CPU cycles by carefully making a few small tweaks. I added a bypass for the "program only some chips" mask, because it was adding unnecessary CPU cycles for a feature that is rarely used. I removed the verification feature from the write routine, because we can always verify the data after the write chunk is complete, which is more efficient. I also added assumptions about the initial/final state of the CS/OE/WE pins, which allowed me to remove more valuable CPU cycles from the read/write cycle routines. There are also a few enormous performance optimizations I should have done a long time ago: 1) The code was only handling one received byte per main loop iteration. Reading every byte available cut nearly a minute off of the 8 MB programming time. 2) The code wasn't taking advantage of the faster programming command available in the chips used on the 8 MB SIMM. The end result of all of these optimizations is I have programming time of the 8 MB SIMM down to 3:31 (it used to be 8:43). Another minor issue I fixed: the Micron SIMM chip identification wasn't working properly. It was outputting the manufacturer ID again instead of the device ID.
2020-11-18 05:03:32 +00:00
*/
#ifndef HAL_SPI_H_
#define HAL_SPI_H_
#include "gpio.h"
#include "spi_private.h"
/// CPHA bit in the SPI mode parameter of SPI_InitDevice
#define SPI_CPHA (1 << 0)
/// CPOL bit in the SPI mode parameter of SPI_InitDevice
#define SPI_CPOL (1 << 1)
/// Friendly names for modes 0-3 when dealing with CPHA/CPOL in SPI_InitDevice
#define SPI_MODE_0 (0 | 0)
#define SPI_MODE_1 (0 | SPI_CPHA)
#define SPI_MODE_2 (SPI_CPOL | 0)
#define SPI_MODE_3 (SPI_CPOL | SPI_CPHA)
/// SPI controller
typedef struct SPIController
{
/// The serial clock pin
GPIOPin sckPin;
/// The master out/slave in pin
GPIOPin mosiPin;
/// The master in/slave out pin
GPIOPin misoPin;
} SPIController;
/// SPI device
typedef struct SPIDevice
{
// These two members should be filled in the struct by hand
/// The GPIO pin used for chip select
GPIOPin csPin;
/// The SPI controller this device belongs to
SPIController *controller;
// Everything below here is private
SPIDevicePrivate private;
} SPIDevice;
SPIController *SPI_Controller(uint8_t index);
void SPI_InitController(SPIController *c);
bool SPI_InitDevice(SPIDevice *spi, uint32_t maxClock, uint8_t mode);
void SPI_RequestBus(SPIDevice *spi);
void SPI_ReleaseBus(SPIDevice *spi);
void SPI_Assert(SPIDevice *spi);
void SPI_Deassert(SPIDevice *spi);
uint8_t SPI_RWByte(SPIDevice *spi, uint8_t b);
#endif /* HAL_SPI_H_ */
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