{"action":"created","issue":{"url":"https://api.github.com/repos/simon-jouet/ESP32Controller/issues/4","repository_url":"https://api.github.com/repos/simon-jouet/ESP32Controller","labels_url":"https://api.github.com/repos/simon-jouet/ESP32Controller/issues/4/labels{/name}","comments_url":"https://api.github.com/repos/simon-jouet/ESP32Controller/issues/4/comments","events_url":"https://api.github.com/repos/simon-jouet/ESP32Controller/issues/4/events","html_url":"https://github.com/simon-jouet/ESP32Controller/issues/4","id":389330156,"node_id":"MDU6SXNzdWUzODkzMzAxNTY=","number":4,"title":"[Not an Issue] Hint on I2S Parallel DMA and shift register stepper driving","user":{"login":"Aggebitter","id":8456282,"node_id":"MDQ6VXNlcjg0NTYyODI=","avatar_url":"https://avatars0.githubusercontent.com/u/8456282?v=4","gravatar_id":"","url":"https://api.github.com/users/Aggebitter","html_url":"https://github.com/Aggebitter","followers_url":"https://api.github.com/users/Aggebitter/followers","following_url":"https://api.github.com/users/Aggebitter/following{/other_user}","gists_url":"https://api.github.com/users/Aggebitter/gists{/gist_id}","starred_url":"https://api.github.com/users/Aggebitter/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Aggebitter/subscriptions","organizations_url":"https://api.github.com/users/Aggebitter/orgs","repos_url":"https://api.github.com/users/Aggebitter/repos","events_url":"https://api.github.com/users/Aggebitter/events{/privacy}","received_events_url":"https://api.github.com/users/Aggebitter/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":15,"created_at":"2018-12-10T14:37:42Z","updated_at":"2018-12-17T05:02:18Z","closed_at":null,"author_association":"NONE","body":"I have thinking a lot about this I2S to a shift register. The time resolution should be good and look at this driver for RGB displays:\r\nhttps://github.com/mrfaptastic/ESP32-RGB64x32MatrixPanel-I2S-DMA\r\nhttps://github.com/ESP32DE/I2S_parallel_example_drive_a_64x32_display\r\n\r\nfrom thread:\r\nhttps://esp32.com/viewtopic.php?f=17&t=3188"},"comment":{"url":"https://api.github.com/repos/simon-jouet/ESP32Controller/issues/comments/447723488","html_url":"https://github.com/simon-jouet/ESP32Controller/issues/4#issuecomment-447723488","issue_url":"https://api.github.com/repos/simon-jouet/ESP32Controller/issues/4","id":447723488,"node_id":"MDEyOklzc3VlQ29tbWVudDQ0NzcyMzQ4OA==","user":{"login":"ekettenburg","id":20956677,"node_id":"MDQ6VXNlcjIwOTU2Njc3","avatar_url":"https://avatars3.githubusercontent.com/u/20956677?v=4","gravatar_id":"","url":"https://api.github.com/users/ekettenburg","html_url":"https://github.com/ekettenburg","followers_url":"https://api.github.com/users/ekettenburg/followers","following_url":"https://api.github.com/users/ekettenburg/following{/other_user}","gists_url":"https://api.github.com/users/ekettenburg/gists{/gist_id}","starred_url":"https://api.github.com/users/ekettenburg/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ekettenburg/subscriptions","organizations_url":"https://api.github.com/users/ekettenburg/orgs","repos_url":"https://api.github.com/users/ekettenburg/repos","events_url":"https://api.github.com/users/ekettenburg/events{/privacy}","received_events_url":"https://api.github.com/users/ekettenburg/received_events","type":"User","site_admin":false},"created_at":"2018-12-17T05:02:18Z","updated_at":"2018-12-17T05:02:18Z","author_association":"NONE","body":"@misan - since the 74lv595 and 74hv595 are completely interchangeable and direct drop in replacements I guess it probably doesn't matter as long as the clock can be set in configuration - for instance looking at one of my printers (coreXY belt driven RAMPS printer) even at 500 mm/sec the step speed would be 25,000 steps/sec or 50,000 pin changes/sec (on and then off) or 50khz\r\n\r\nNow my math might be totally wrong here but it takes more or less 40 ticks of the clock per pin change, and at 2V the max clock 5Mhz (worst case - no value given for 3.3V) - so at 2V you could get 125khz in pin changes (across 32 bits) or 75khz in steps? still far beyond your average printers need for even crazy fast speeds. The only printer I've worked on that wouldn't be satisfied by 5Mhz clock would be a heavily geared very large format printer. Unless my math is totally wrong.... \r\n\r\nAlso worth noting that Marlin running on a standard ATMEGA2560 board starts using double and quad steps above 10khz and 20khz respectively - so if say even 75khz was supported by an ESP32 and a shift register it would be far beyond ATMEGA2560 capabilities - and smoothieboard/duet/etc are in the 100-200khz range (https://reprap.org/wiki/Step_rates). If say 10MHZ is acceptable clock at 3.3V (data sheet doesn't say but based on the jump from 2V to 4.5V) that'd be 150khz max steps?\r\n\r\nAgain my math might be wrong - but if it is at least close then I think there should be no concern about using the SN74HC595 other than allowing the clock frequency to be set low enough for it to be reliable across temperatures at 3.3v (whether that's 5MHZ the safe 2V value or something like 10MHZ I don't know) because the step rates will be plenty high\r\n\r\n"}}
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