| @MEGASCOPE |
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Megascope project contains a lot of subprojects, different external ADC data capture devices could be used,
based on AVR or PIC microcontrollers: - ATMEGA88 - PIC12F675 - ATMEGA8535 - PIC18F4455/PIC18F4550:ADC08100:32kB_SRAM - LPTscope support coming soon If no external devices present, it could be used with soundcard as data input source. Win32 based application, but runs well under Linux too, if executed under Wine environment. Software download is available here. Also it is recommended to download a freeware functional signalgenerator fg_lite. |
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ATMega88 based scope. 4-channel scope suitable for different measuments. Very low-speed (timing in multiple seconds) signals inspection is most perfect. High-speed signals inspection may have some AVR internal ADC caused noises. Maximum sampling speed is about 4,5us, limited with AVR internal ADC speed. Schematics is simple and requires a few components. So for PCB was choosen prototyping PCB and no layout given here. Should be assembled according to schematics. 
Microcontroller software: C HEX |
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ATMega8535-ADC0820 based scope. 2-channel scope, with input signal range of 5V and 2,5V. Maximum sampling speed is about 1,6us. Not bad to inspect signals above 100kHz. Uses 32kB SRAM (Static RAM). Those chips, with 15ns access time, can be found "for no bucks" on old 486 motherboards, DIL28 socket. 
Microcontroller software: C HEX |
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PIC12F675 based very simple scope. 1-channel scope, with input signal range of 5V. Maximum sampling speed is limited by RS232 transfer speed to 11-15kSPS, as chip does not have much internal RAM. Chip internal ADC is even pretty good on high speed samplings (works good at 1,6us), but RS232 transfer after each captured byte, turns down average speed. Here you can see an experimental version of that kind of scope. An idea itself becomes from scope which can be found at Semifluid projects pages. Just i did not found this scope running on JAL software working well. Any modifications did not help at all. Problem seems to sit inside of JAL libraries where it does not correct operations with RS232 interface and ADC also is messed up or just may JAL version did not match with sources. So I decided to make own version of simplest scope based on PIC12F675. It does not need external power supply. Power is taken directly from DTR-RTS outputs, driven to high state by PC software. Project does have 2 versions: - one similar to Semifluid's one - running on 20MHz crystal/resonator - and second one running on internal clock at 4MHz. The first one might have a minimal speed advance, but it is really minimal, becauce speed most depends of RS232 tranferrate and is a near or above of 10kSPS. Not much:) but it works and is very simple! Version which runs on internal 4MHz clock, needs somekind of OSCCAL tune-up for correct RS232 baudrate. For tuning it is recommended to use my RS232 baudrate tune-up examples. Schematics: 20Mhz version 4Mhz version Microcontroller software: ASM HEX RS232 transfer baudrate & osccal frequency tune-up software: ASM |
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PIC18F4455-ADC08100 based scope. Project is in development state. |
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