Questions tagged [6800]
Motorola 6800 family of processors. This does not include the similarly-numbered but different 6809 family.
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What elements of the MOS 6502 did it copy from the Motorola 6800?
It is not uncommon for microprocessor system designers to copy elements of
design from other microprocessor systems; the Z80, extensively copying
design elements of the 8080, is a notable example.
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Does this 1978 code for a 6800 really clear ALL of memory?
On page 43 of the October 1978 Dr. Dobb's Journal (reprinted in Volume 3 Page 425 Issue 10 Number 29) is a letter to the editor giving three 6800 routines to clear ALL of memory, stating...
Routine ...
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Can anyone help me identify what 6803/6303 development tools might have been used to build this program?
I've been doing some hobby work reverse-engineering vintage synthesizer ROMs from the early 80s, and I'm curious about what kind of development tools the original engineers may have used. Normally ...
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Is there a common name for this 'switch' like 6800 assembly routine?
I've been reverse-engineering a 6303/6800 binary from the early 1980s, which includes a subroutine for jumping to one entry in a table of relative offsets in memory, based upon whether the value of a ...
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How did the MC6800 get its name?
The 68000 was allegedly named for its (approximately) 68k transistors, and to imply some sort of relation to Motorola’s first microprocessor, the 6800.
But then how did Motorola pick the name “6800”?
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Any recommendations for a Hitachi HD6303 assembler?
Does anyone have any good recommendations for a Hitachi HD6303 assembler?
I've been working on a project to reverse-engineer an executable made for a Hitachi HD63B03 processor. I've finished the first ...
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How common was programming in C targeting 8-bit processors in 1983?
How often was C used to program firmware for 8-bit processors in the early 80s?
I'm reverse engineering a firmware binary for a device built around a Hitachi 6303 processor, manufactured in 1983. Even ...
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What were the modifications on the Apple 1 board that would have made it 6800 compatible?
The Apple-1 motherboard was designed in such a way as to make it possible for the hobbyist to remove the 6502 processor and use a Motorola 6800 as the CPU instead. This was not a trivial operation, as ...
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What does the DAA instruction do?
The 6502 has the decimal mode, which causes the ALU to always output valid BCD if it's given valid BCD. Of course, you can turn it off, as any sane person always does.
I was just looking at the ...
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Why did the SWTPC 6800 Computer System not take off? [closed]
In 1974, a major semiconductor company released its first 8-bit CPU that was good enough to build a serious computer around. In 1975, a smaller company built a computer around it, a horizontal box ...
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Why was the SWTPC 6800 Computer System cheaper than the Altair?
In 1974, Intel released the 8080, which basically was the first microprocessor good enough to build a serious computer around. That led to the Altair 8800 the following year, which was the beginning ...
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Does the 6800 always handle unaligned access correctly?
I asked a similar question about the Intel 8080 to which I guessed the answer would probably be yes, because later Intel CPUs did fully handle unaligned access.
I am less sure about the Motorola 6800, ...
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6800 I flag at reset
I have written an emulation of the Heathkit ET-3400A microcomputer trainer in Java, mainly to see if I could do it and to get my feet wet in Java. Odd question, but there's a discrepancy (one of many,...
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How to code for bidirectional I/O for MC6850 ACIA (680x Assembler)
I need a code listing for 6802 (or 6809) to initialize and set the 6850 ACIA into bidirectional serial I/O mode.
I have two vintage boards and need to get the ports working and connected before I can ...
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Where can I find the Motorola Application Note AN-754?
Urgently need a copy of Motorola Application Note AN-754 "Device Operation and System Implementation of the Asynchronous Serial Interface Adapter".
I have two boards from college days (1979) ...