clock mode in P89c668

[eagle]

Hello!

I work with a P89C668. In this uC you can work with 6 mode clock (default) and 12 mode clock (default), but i don't know as changing this modes. Are There Anybody what know this?

When i switch on the uC in first time, itself put in 12 mode clock, and i want to change or it isn't possible, then for other time as i must do it so that is way 6 mode clock.

Thanks.

[Andy Ayre]

This is a quote from the datasheet:

"This device is configured at the factory to operate using 6 clock periods per machine cycle, referred to in this datasheet as "6 clock mode". (This yields performance equivalent to twice that of standard 80C51 family devices). It may be optionally configured on commercially-available EPROM programming equipment to operate at 12 clock periods per machine cycle, referred to in this datasheet as "12 clock mode". Once 12 clock mode has been configured, it cannot be changed back to 6 clock mode."