Login

Back to forum Reply to this topic Go to last reply Posted By SVS on 2016-01-22 14:24:18  Command UI- on 1541 I suppose only few of us had used this odd command. But it is said it sets the 1541-drive to emulate the 1540. I read that the drive becomes "faster" Are these rumors or really this command makes speed(er) read operations? Posted By Chicken on 2016-01-22 18:02:31  Re: Command UI- on 1541 It's the (not so) well known "VIC20 mode". I tested this decades ago. The drive responds "normally" (in contrast to using this mode on a C64 – which won't work). However, loading was just (if at all) marginally faster. Edit: Not at home, so I didn't want to login. But spam protection made me I just head a déjà vu … Talking about 1551 detection in the other thread and "UI-" here. I knew this "happened" before. And I remembered where and found it … in Mike Dailly's blog: https://www.blogger.com/comment.g?blogID=17487316&postID=3556243265765451151&bpli=1 Scroll down to my comment or read here: "jsr $eda9 bcc 1551 is used On plus/4 and 1541 drives the "UI-" (ElCheapo speeder ) works if the screen is switched off." So SVS, don't forget to change $ff06 before loading Posted By siz on 2016-01-23 02:45:10  Re: Command UI- on 1541 The VIC-20 doesn't have badlines and the 1540's serial bus timing was set to the tightest possible on that. With the C64 and it's badlines introduced the 1540's serial bus timing was too fast and they slowed it down a bit to create the 1541. Fun fact: the only difference between the 1540 and the first revision of 1541 is the ROM and the badge. This UI- command sets the 1541 back to the original 1540 (VIC-20 compatible) serial bus timing. No other operations (ie. disk access) is modified. Back to top Reply to this topic Copyright © Plus/4 World Team, 2001-2024. Support Plus/4 World on Patreon