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https://github.com/dougg3/mac-rom-simm-programmer.git
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7425af761a
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.
56 lines
1.2 KiB
C
56 lines
1.2 KiB
C
/*
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* gpio.h
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*
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* Created on: Nov 14, 2020
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* Author: Doug
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*/
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#ifndef HAL_GPIO_H_
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#define HAL_GPIO_H_
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#include <stdint.h>
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#include <stdbool.h>
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/// Creates a temporary GPIOPin struct. Used when assigning to a GPIOPin variable.
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#define GPIO_PIN(port, pin) ((GPIOPin){port, pin})
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/// A NULL GPIO pin
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#define GPIO_PIN_NULL ((GPIOPin){0xFF, 0xFF})
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/// The GPIO pin struct
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typedef struct GPIOPin
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{
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/// The port the pin belongs to
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uint8_t port;
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/// The index of the pin on the port
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uint8_t pin;
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} GPIOPin;
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void GPIO_SetDirection(GPIOPin pin, bool output);
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void GPIO_SetPullup(GPIOPin pin, bool pullup);
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void GPIO_SetOn(GPIOPin pin);
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void GPIO_SetOff(GPIOPin pin);
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void GPIO_Toggle(GPIOPin pin);
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bool GPIO_Read(GPIOPin pin);
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/** Sets whether a GPIO pin is outputting high or low
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*
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* @param pin The pin
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* @param on True if it's high, false if it's low
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*/
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static inline void GPIO_Set(GPIOPin pin, bool on)
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{
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on ? GPIO_SetOn(pin) : GPIO_SetOff(pin);
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}
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/** Determines if a GPIO pin is null
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*
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* @param pin The pin
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* @return True if it's null, false if not
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*/
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static inline bool GPIO_IsNull(GPIOPin pin)
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{
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return pin.pin == 0xFF && pin.port == 0xFF;
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}
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#endif /* HAL_GPIO_H_ */
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