| ??? 10/05/07 09:32 Read: times |
#145452 - 6-clocker Responding to: ???'s previous message |
Russell Kramer said:
I am using a P89V51RD2. the Program Counter advances every twelve cycles of the clock. Is there a way to change this such that the advancement occurs after fewer clock pulses? In the P89V51RD2, there is an option to switch it to 6-clock mode - set the appropriate tick in FlashMagic while programming (if you are using a parallel device programmer, consult the manual or manufacturer of that programmer on how to set the various fuses). Nevertheless, it is imprecise to say "Program Counter advances every twelve cycles", this is simply not true. PC advances each instruction cycle (which is 12/6 clock cycles in the P89V51RD2) ONLY if you are executing instructions which length is twice the execution time - i.e. 2-byte instructions taking 1 instruction cycle (in fact this is the only combination). In each other situations, the PC advances only as much as many bytes the instruction takes. JW |
| Topic | Author | Date |
| Clock Frequency | 01/01/70 00:00 | |
| 6-clocker | 01/01/70 00:00 | |
| And don't forget ... | 01/01/70 00:00 | |
| Instruction Timings... | 01/01/70 00:00 | |
| Maybe it would be less confusing ... | 01/01/70 00:00 | |
per instruction cycle | 01/01/70 00:00 |