As an addendum I had a lovely conversation with WDC while trying to debug my board, and they confirmed that yes you can use oscillators for CLK and FCLK. They also mentioned that you won't get any output on FCLKO until after the chip been reset. It's a nice indicator if the CPU is actually working ...

Something they used to do for automatic assembly of boards with parts on both sides is to put a tiny spot of epoxy under each part that goes on the bottom, so it wouldn't fall off in the soldering process. If you've tried that for hand-soldering, I'd be interested in how it went. An assembly house ...

(BTW, the next standard size up from 0402 chip capacitors and resistors is 0603, not 0604.)
Welcome to the dumb mistake I make nearly ever week lol.

It is a dual sided load, but I have to be careful where I place components as the battery will be on the back. I am making a project that is about ...

For the '134, at least, the datasheet does contain the answer, although it's not as blatantly overt as one might wish.

'134 oscillator pins.png Table 1-6 suggests that the CLK and FCLK functions aren't subject to any control bits.

And Section 2.4 clearly says that CLK and FCLK are inputs ...

A 3.2mm x 2.5mm oscillator has a surface area of 8 sq mm. A 2.5mm x 2mm oscillator has a surface area of 5 sq mm.

Four 0604 passives and a 1.2mm x 1 mm crystal (assuming I wanted to use one that small and it met my specs) are 6.22 sq mm before you get to inter component spacing. So using an ...

Bare crystals, with crystal accuracy, are available much smaller than complete crystal oscillators are, like a chip capacitor, just a little longer; so I think you can go with what's called out and still meet your goals better than a complete oscillator will. The resonators that are not as accurate ...

Forgive me if I am being obtuse but can one use an oscillator with the W65C134S/W65C265S instead of the specified crystal resonator circuit?

Most datasheets I have read call out if that is a possibility, sometimes requiring different configuration if one is being used. The WDC datasheet is silent ...

There's a table at the bottom of page 2 in the manual titled "Register Address Map" showing the CS relationship. As Garth said, many 65xx IO chips used that configuration so I implemented on my design as well.


Yeah for whatever reason I just wasn't seeing it. Brain got hung up on the slightly ...

Awesome, thank you. Everything has clicked into place now

Forgive me, I am apparently being dense, but I am having trouble understanding the relationship between CS1 and /CS2 .

I am working on a W65C265 project, I have done a few in the past, but this time I need SPI support. I have programmed a XC9572XL to be a 65SPI. The interface makes sense, except ...