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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.
45 lines
1.3 KiB
C
45 lines
1.3 KiB
C
/*
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* parallel_bus.h
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*
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* Created on: Nov 26, 2011
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* Author: Doug
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*/
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#ifndef HAL_PARALLEL_BUS_H_
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#define HAL_PARALLEL_BUS_H_
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#include <stdint.h>
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#include <stdbool.h>
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void ParallelBus_Init(void);
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void ParallelBus_SetAddress(uint32_t address);
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void ParallelBus_SetData(uint32_t data);
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void ParallelBus_SetCS(bool high);
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void ParallelBus_SetOE(bool high);
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void ParallelBus_SetWE(bool high);
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void ParallelBus_SetAddressDir(uint32_t outputs);
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void ParallelBus_SetDataDir(uint32_t outputs);
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void ParallelBus_SetCSDir(bool output);
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void ParallelBus_SetOEDir(bool output);
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void ParallelBus_SetWEDir(bool output);
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void ParallelBus_SetAddressPullups(uint32_t pullups);
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void ParallelBus_SetDataPullups(uint32_t pullups);
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void ParallelBus_SetCSPullup(bool pullup);
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void ParallelBus_SetOEPullup(bool pullup);
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void ParallelBus_SetWEPullup(bool pullup);
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uint32_t ParallelBus_ReadAddress(void);
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uint32_t ParallelBus_ReadData(void);
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bool ParallelBus_ReadCS(void);
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bool ParallelBus_ReadOE(void);
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bool ParallelBus_ReadWE(void);
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void ParallelBus_WriteCycle(uint32_t address, uint32_t data);
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uint32_t ParallelBus_ReadCycle(uint32_t address);
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void ParallelBus_Read(uint32_t startAddress, uint32_t *buf, uint16_t len);
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#endif /* HAL_PARALLEL_BUS_H_ */
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