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builderpages:plasmo:tinyz280 [2018/02/08 10:08]
builderpages:plasmo:tinyz280 [2018/03/23 22:50] (current)
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 ==== Step 2, CF Bootstrap ==== ==== Step 2, CF Bootstrap ====
-Blahblahblah+(2/11/18) CF Bootstrap is working. The pc board is modified to add a jumper that switch between UART bootstrap and CF bootstrap. The reset connection (T14 & T15) is cut and a new output signal from CPLD is now control the reset of the Z280. This is all the physical modifications required. There are significant more firmware and software changes: 
 +New CPLD with CF bootstrap state machine (CFinit) and modified memory map. Here is the{{:​builderpages:​plasmo:​tinyz280:​tinyzramcf.pdf|schematic}} ​ and the {{:​builderpages:​plasmo:​tinyz280:​tinyzramcf_program_file.zip|programming file}}. The state machine design is rather convoluted. Here is the [[:​builderpages:​plasmo:​tinyz280:​cfboot_operation|theory of operation]]. 
 +CF Bootstrap software is evolving. The current approach is a small (~128 byte) cold bootstrap code located in boot sector of a CF. Before Z280 reset is releasedthe CFinit state machine configured the CF to stream cold bootstrap code out to CF's 16-bit data port. After reset Z280 will execute the code stream which copy a small boot loader into 0x1000 and jump to it whichin turn, load data from sector 2 and 3 and execute. Here is the{{:​builderpages:​plasmo:​tinyz280:​cfmonldr.zip|cold}} ​ {{:​builderpages:​plasmo:​tinyz280:​cfmonldr.zip| bootstrap code}}. Here is the utility program to copy cold bootstrap into boot sector. Another utility program to copy software into sector 2 & 3 of CF. The two utility programs will be combined later.
 ==== Step 3, CF Bootstrap with DRAM ==== ==== Step 3, CF Bootstrap with DRAM ====
-more blah, blah+Blah, blah, blah 
 +==== Final Step, Putting it all together ==== 
 +After the various steps of incremental development,​ this is the [[:​builderpages:​plasmo:​tinyz280:​final_step|end product]].
builderpages/plasmo/tinyz280.1518102494.txt.gz · Last modified: 2018/02/08 10:08 by plasmo
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