| ??? 02/10/09 21:11 Read: times Msg Score: +2 +2 Good Answer/Helpful |
#162258 - The key is the Clock Distribution Responding to: ???'s previous message |
Clock Distribution varies among '51 derivatives
For Example: NXP P89V51RB2_RC2_RD2 http://www.nxp.com/acrobat_download/datasheets/P89V51RB2_RC2_RD2_4.pdf page 27 "In the ‘Timer’ function, the register is incremented every machine cycle. Thus, one can think of it as counting machine cycles. Since a machine cycle consists of six oscillator periods, the count rate is 1/6 of the oscillator frequency." ATMEL AT89LP2052 http://www.atmel.com/dyn/resources/prod_documents/doc3547.pdf page 7 "Timer/Counters The Timer/Counters increment at a rate of once per clock cycle. This compares to once every 12 clocks in the standard 8051." ATMEL AT89S2051_4051 http://www.atmel.com/dyn/resou...oc3390.pdf page 5 X2 Mode Description The clock for the entire circuit and peripherals is normally divided by 2 before being used by the CPU core and peripherals. This allows any cyclic ratio (duty cycle) to be accepted on XTAL1 input. In X2 mode this divider is bypassed. Figure 6-1 shows the clock generation block diagram." It would be more helpful if the OP provide more details about the specific 89C51 derivative MCU. Then there will be a detailed answer about how to achive 115200 baudrate to UART serial port. K.L.Angelis |
| Topic | Author | Date |
| How to set baud rate 115200 in 89c51 | 01/01/70 00:00 | |
| no | 01/01/70 00:00 | |
| yes if you have a six clocker and better | 01/01/70 00:00 | |
| 6 clock mode has NOTHING to do with timers | 01/01/70 00:00 | |
| but it will affect the throughput | 01/01/70 00:00 | |
| The key is the Clock Distribution | 01/01/70 00:00 | |
| I would be surprised... | 01/01/70 00:00 | |
| Plenty of options for UART | 01/01/70 00:00 | |
| Throughput | 01/01/70 00:00 | |
Thanks | 01/01/70 00:00 |