| ??? 01/28/11 14:20 Modified: 01/28/11 14:24 Read: times |
#180879 - Sub-question Responding to: ???'s previous message |
I have looked at my old data to try and refresh my memory. The "newest" UART that I could find was the Intersil IM6402 which never had a 9 bit mode. It was current with the 8051 so I don't think the idea of a hardware address bit existed in the UART domain. It was a single supply version of an industry standard UART.
As I remember the 8051 was not only the first microcontroller to have a 9 bit mode, it was the first to have a UART. Before that I either had to "bit-bang" or use an 8251. Certainly the 8251 predated the 8051 and it did not have the 9th bit. My gut feel is that Intel did invent the 9th bit, but the question may devolve into: Did the concept of a dedicated address bit exist before in the application level. The MC14469 employed the 8th bit as an address indicator. I know it postdated the 8051, but perhaps the concept did exist earlier. |
| Topic | Author | Date |
| Origins of 9-bit, "Multiprocessor" UART mode? | 01/01/70 00:00 | |
| do not know, but | 01/01/70 00:00 | |
| begged question | 01/01/70 00:00 | |
| Pre-'51 | 01/01/70 00:00 | |
| I do not remember... | 01/01/70 00:00 | |
| Not remembering == Don't recall reading | 01/01/70 00:00 | |
| Have you forgotten 68xx? | 01/01/70 00:00 | |
| No list of model numbers, so nothing to have forgotten | 01/01/70 00:00 | |
| How I spent my time | 01/01/70 00:00 | |
| Yes | 01/01/70 00:00 | |
| Motorola not forgotten | 01/01/70 00:00 | |
| Have you forgotten your rule... | 01/01/70 00:00 | |
| Sub-question | 01/01/70 00:00 | |
| Parity | 01/01/70 00:00 | |
| Works both ways | 01/01/70 00:00 | |
| LOL | 01/01/70 00:00 | |
| I don't think so | 01/01/70 00:00 | |
| Exactly | 01/01/70 00:00 | |
| Still don't think so | 01/01/70 00:00 | |
oscillation in system | 01/01/70 00:00 | |
| Cross-Post | 01/01/70 00:00 | |
| Hee Hee... | 01/01/70 00:00 |