| ??? 04/17/06 08:25 Read: times |
#114359 - 9-bit Responding to: ???'s previous message |
Shabeer Badarudeen said:
1.What is the main difference between 8 bit and 9 bit transmission? Err... 1 bit! In gerneral RS232 terms, "8-bit" refers to the number of payload data bits; ie the number of bits transmitted excluding start, stop, and parity. "9-bit" is is a special feature of the 8051[1] specifically designed for multiprocessor communications; the 9th bit is intended for use to distinguish between "address" and "data" bytes - but you can devise your own scheme, if you want... See page 9 in Chapter 3 of the so-called "bible" for the 8051: Chapter 3 - 80C51 Family Hardware Description: http://www.semiconductors.philips.com/acrobat/v...WARE_1.pdf See: http://www.8052.com/forum/read.phtml?id=60891 See also: http://www.8052.com/forum/read.phtml?id=111015 Note that PCs do not directly support 9-bit RS232. 2.Where 9 bit transmissions used? In multiprocessor communication applications! The MDB-ICP used within vending machines is one example: http://www.8052.com/forum/read.phtml?id=113178 when using 9 bit transmission the 9th bit will automatically genereted or we fill it?(parity bit) See the description of RB9 in the above-mentioned "bible" chapter. You can use this to implement parity of you want - but it is not automatic. [1] and also some other processors |
| Topic | Author | Date |
| 9 bit transmission | 01/01/70 00:00 | |
| 9-bit | 01/01/70 00:00 | |
| c programme to apply to microcontroller | 01/01/70 00:00 | |
| OK | 01/01/70 00:00 | |
see how muich easier it is to read | 01/01/70 00:00 | |
| Hypoterminal | 01/01/70 00:00 |