P89C51RD2HXX 6clk mode to 12 clock mode problem

[Haroldo Lage]

Hi all,

I have a firmware developed to an 80C51 on 12 clock mode chip. I'm had to change to P89C51RD2HXX, but this 6 clock/ 12 clock matter is causing sincro problems.
On the datasheet "P89C51RB2_RC2_RD2_9.pdf" provided by philips it is written that "may be optionally configured on commercially-available EPROM programming equipment to operate at 12 clocks per machine cycle", but there is no information about this comercial-available programmer.
I'd like to know what this programmer does to change to 12 clock mode.

I'm sorry to send this little off-topic subject.

Thank you for the attention

Haroldo Lage
Brazilian Firmware Programmer

[erik malund]

"I'd like to know what this programmer does to change to 12 clock mode."
ANY commercial programmer with the device in the device list (should be most if not all).

Erik

[Haroldo Lage]

Hi Erik, thanks for the reply

But I wanted to know in details what it does, which bit is set, where this bit is located and so on.

Thanks in advance,

Haroldo Lage

[Andy Ayre]

The only way to access the bit is via a parallel programmer. It does not have a memory address in the device to allow you to read it.

It simply changes the device from the default of 6 clocks/cycle to 12 clocks/cycle. Once set it cannot be unset.

[HSon]

yes there is... CKCON.. Clock Control at D8H.... look at the datasheet

[Andy Ayre]

The CKCON SFR is only implemented on the newer 89C51Rx2xx devices, which can be changed between 12 clocks/cycle and 6 clocks/cycle in software.

The CKCON SFR does NOT exist on the older 89C51Rx2Hxx device. Note the 'H' in the part name. This discussion is about the older devices, not the newer ones. Although the parts have similar names, they are NOT THE SAME.

[HSon]

P89C51RD2HXX....'H' is the older or first generation. P89C51RD2XX... 2nd generation. H series default to 6clock optional program to 12clock. BUT it can not be reprogram back to 6clock, OTP. The non-'H' 2nd generation is default to 12clock and can be program to 6clock and can be reprogram back to 12clock. ...look at the device comparison table
http://www.semiconductors.philips.com/acrobat/datasheets/P89C51RA2_RB2_RC2_RD2_2.pdf page 3.

[erik malund]

If it is only a few devices, your supplier should be able to blow the 12clock fuse for you.

Erik

[HSon]

Erik,
nah... we dont want to take the easy way out.... the device maker offers a way.. . and we want to know the way.

[Andy Ayre]

What way? I really an cunfused as to what you are asking? It's very simple:

Parts with 'H' in the name require a parallel programmer.

Parts without 'H' in the name can be changed with Flash Magic or a parallel programmer.

Thats all there is to it.