On 2012-09-17, at 06:45, Jim Brain wrote: >> >> After thinking about it for a bit... You can also use a 74LS00 (or 74HCT00) which is fully used up in the process and has 2 pins less: >> > > Looking at the original schematic, I sketched one up using a '148 and a '257. With the '257 as Gerrit suggested (the NAND idea would also work) and the 148 handling the 3 signals. The '148 takes care of OE/CE with it's GS pin (14), and the design requires just 2 ICs and 1 resistor (to hold the CHARROM switch position in high unless shorted through the switch/jumper. The NAND version looks like this: https://dl.dropbox.com/u/58002657/rom_replacement_nand.png It has four pull-up resistors. One would of course be better. So you mean you used 148 in place of LS11 and 257 for the second one (interchangeable with 00), right? -- SD! Message was sent through the cbm-hackers mailing listReceived on 2012-09-17 11:00:05
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