Hi list, That is the question, indeed !
My AVR project currently is based on a mega32 (selected 3+ years ago), which has a single USART. I actually need two serial links, but since they are mutually exclusive (when I work on one, I don't need to work on the other), it could be possible to reconfigure the USART every time, and add some extra external circuitry to switch the Rx/Tx pins from one serial link to the other. But I discovered recently on AVRfreaks, that there is a cool mega324 variant which is basically a mega32 with a second USART. So this 324 would make my life much easier ! At the same time I am about to switch my project from a text LCD module, to a graphical one, which means increased RAM and code memory requirements, so I was logically eyeing the 644 instead of the 324. Problem: I am seeing conflicting information about the 644. On AVRfreaks, the datasheet they give, which is specific to the 644, says that unlike the 324, and quite strangely, it does NOT have this second USART !? :-/ OTOH, if I go on the Atmel website, they provide a unified datasheet for the 3 variants: 164/324/644, and this paper clearly indicates that ALL THREE variants, do have that second USART. Since that USART is the only reason I am considering a 644, it's rather important that I know the truth ! ;-) I looked in the ERRATA sections of the two datasheets, and neither mention errors regarding the available peripherals. All I noticed is that the document # in the footer of the datasheets, suggests that the datasheet on AVRfreaks is older (#2593) than the one on the Atmel website (#8011). Still, lacking any errata, I can only consider the two datasheets as valid. So that can only mean that the 644 started it's life with one USART, and got one later on, probably to make it consistent with the other variants in the same series, 164 and 324. So, how do I know if the 644 I will order, will come with one or two USARTs, grrr... If someone knows the story about the 644 and could shed some light, I am all ears ! ;-) Regards, -- Vince, confused to say the least... _______________________________________________ AVR-chat mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/avr-chat
