ColdFire/68K Microcontrollers and Processors中的主题 Re: Error in MC68000 user's manual?

Error in MC68000 user's manual?

mhjacobson — Mon, 16 Feb 2026 01:24:59 GMT

Hello,

I have noticed what may be an error in the MC68000 user's manual (as posted at this URL on NXP's Web site).

In section 5, in figure 5-4 ("Word and Byte Read-Cycle Timing Diagram"), the bottom line shows time intervals labelled "READ", "WRITE", and "READ". However, if I'm not mistaken, all three of those intervals are reads. The first is a word read (both LDS and UDS asserted); the latter two are byte reads (only LDS and only UDS asserted, respectively).

Please let me know if I've misunderstood.

Thank you.

Re: Error in MC68000 user's manual?

mhjacobson — Mon, 16 Feb 2026 01:26:44 GMT

Here is an image of the figure in question.

Re: Error in MC68000 user's manual?

TomE — Mon, 16 Feb 2026 05:47:08 GMT

That's fairly obviously a cut-and-past bug from Figure 5.3. That has been edited to make Figure 5.4, but they forgot to change the last line where the "Write" label is.

Those manuals were brilliant. That one is the 9th edition, dated 1993 or 2006. Nothing like their later manuals...

https://community.nxp.com/t5/i-MX-Processors/i-MX53-i-MX6-Reference-Manual-Spelling-Problems/m-p/341061

Tom

Re: Error in MC68000 user's manual?

Bio_TICFSL — Mon, 16 Feb 2026 14:15:31 GMT

Good!