Was the swap more common on boards with fast ROM? A ROM uses less power when deselected through /CS, but it reacts faster to assertion of /OE.qwertymodo wrote:the only difference is the chip select pin (or sometimes the output enable is used instead, Nintendo seemed to swap /CS and /OE whenever they felt like it because it really didn't matter for MaskROMs).
Unless you're on NES and your MMC1 uses +CE as its primary chip enable.Sometimes you will also see a CE2 on SRAM, but what that actually does is that you tie it to the Vcc rail through a pull-up resistor and it disables the chip until the voltage rail is stable, so while it is a secondary chip enable, you would not use it as a chip select.