histcomp:altair_8800

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histcomp:altair_8800 [2023-12-06 07:56] – asdfhistcomp:altair_8800 [2024-04-29 22:59] (current) – [Emulation] asdf
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 ====== Altair 8800 ====== ====== Altair 8800 ======
-A kit-based home computer originally released in 1975 and largely credited with sparking the home computer revolution. Much like mainframes and minicomputers of the time, its front panel featured a number of toggle switches for entering programs and examining memory.+A kit-based home computer originally released in 1975 and largely credited with sparking the home computer revolution. 
  
 ===== Hardware ===== ===== Hardware =====
 ==== Front panel ==== ==== Front panel ====
-The data LEDs show the contents of the CPU's incoming data bus. These lines are pulled up on a memory write regardless of the data being written. Likewise, the address LEDs display the contents of the address bus or two copies of the I/O port number on I/O instructions. +Much like mainframes and minicomputers of the time, its front panel featured a number of toggle switches for entering programs and examining memory. The data LEDs show the contents of the CPU's incoming data bus. These lines are pulled up on a memory write regardless of the data being written. Likewise, the address LEDs display the contents of the address bus or two copies of the I/O port number on I/O instructions. 
  
 There are also a series of status lights. These sample the 8080's status pins directly at the beginning of each machine (bus) cycle.  There are also a series of status lights. These sample the 8080's status pins directly at the beginning of each machine (bus) cycle. 
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 ==== SIO ==== ==== SIO ====
 +The SIO provides a single serial in/out port. By default, it is assigned to I/O ports 0 (control) and 1 (data). 
 +
 +
 +^      ^ 7 ^ 6 ^ 5 ^ 4 ^ 3 ^ 2 ^ 1 ^ 0 ^
 +^ low | output device ready | not used | data available (a data word is buffered) | data overflow (a new word was received before the previous was passed to the accumulator) | framing error (no valid stop bit) | parity error (received parity does not agree with selected parity) | transmit buffer empty (previous word has been transmitted and a new word may be buffered) |
 +^ high | output device not ready | not used | | | | | | input device not ready |
 +
 +The control channel can also be written to to enable or disable interrupts. Bit 0 controls the input interrupt, and bit 1 controls the output interrupt. Bits 2--7 are ignored. 
 +
 ==== 2SIO ==== ==== 2SIO ====
 +==== ACR ====
 +
 ==== Disk drive ==== ==== Disk drive ====
  
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 [[https://altair32.classiccmp.org/|Altair32]] is probably the most aesthetically appealing simulator available. In addition to its fully-functional front panel, it ships with several images of period software, among them 4K and 8K versions of Altair BASIC. Unfortunately, we have so far been unable to run BASIC or even the [[https://altairclone.com/downloads/killbits.pdf|kill-the-bit game]].  [[https://altair32.classiccmp.org/|Altair32]] is probably the most aesthetically appealing simulator available. In addition to its fully-functional front panel, it ships with several images of period software, among them 4K and 8K versions of Altair BASIC. Unfortunately, we have so far been unable to run BASIC or even the [[https://altairclone.com/downloads/killbits.pdf|kill-the-bit game]]. 
  
-Much more promising is the [[https://adwaterandstir.com/altair/|Altair-Duino]]. As the name implies, it is a hardware replica kit based around an Arduino Due. +Much more promising is the [[Altair-Duino]]. As the name implies, it is a hardware replica kit based around an Arduino Due. 
  
 ===== Sample code ===== ===== Sample code =====
  • histcomp/altair_8800.1701849363.txt.gz
  • Last modified: 2023-12-06 07:56
  • by asdf