•  Back 
  •  Memory / uP 
  •  Index 
  •  Tree View 
  •  Cross references 
  •  Help 
  •  Show info about hypertext 
  •  View a new file 
Topic       : Documentation of the CT60
Author      : Didier MEQUIGNON
Version     : Version 1.03c (July 13, 2005)
Subject     : Documentation
Nodes       : 135
Index Size  : 3674
HCP-Version : 3
Compiled on : Atari
@charset    : atarist
@lang       : 
@default    : 
@help       : 
@options    : -i +z
@width      : 75
View Ref-File7.4.1  Change the CT60 frequency                                  CT60

With the slider inside the page 'Memory / uP' of the CPX, if
necessary it's possible to change the CT60 frequency.

For do this task, a programmable clock generator module using a
CY27EE16 or a DS1085Z-50 must be connected on the CT60's I2C port
with some wires (see also the part 'Programmable clock generator').

The adjustment works by step of 125 KHz between 50 and 110 MHz for
the CY27EE16 (ak-modul-bus module), or by step of 50 KHz between 66
and 110 MHz for the DS1085Z-50 (CTCM module), the value is writed in
RAM for a test after 'OK'. The TOS during the boot when the Atari
logo arrive send equally this value to the clock, but in case of a
problem it's possible to bypass this feature and use the original
frequency by press CTRL or ALT.

 ATTENTION ! 

So long as you not cut the power on the machine, the clock gererator
works with the latest frequency writed inside his RAM. During the
power on sequency, the clock generator copy himself inside his RAM
the original frequency saved in his EEPROM. Press on CTRL or ALT has
no effect if you not cut the power before.

 Initialisation 

The original frequency saved in EEPROM is also modifiable after a
confirmation with a double click on 'Save' but it's very dangerous !

Yet, when it's impossible to restart the computer, the last solution
is to connect the  ak-modul-bus module  on the MODEM 2 port with a
link HE10 SUBD and reprogram in 030 mode the EEPROM of the module
with the 'Save' button. This operation is essential for load a new
module.  The module must be powered by the CT60 and the signals SDA
and SCL must be disconnected because during the 030 mode the CT60
force these signals to 0 ! 



index=119



When it's impossible to restart the computer with the  CTCM module 
you must cut the strap for divide by two the frequency (clock between
33 and 66 MHz), and after reprogram again the module with the CT60 by
saving a new value inside the EEPROM. Now, the frequency is
multiplyed by two when the strap is again in place !

Like the  ak-modul-bus module , the last solution is to connect the 
CTCM module  on the MODEM 2 port with a link HE10 SUBD and reprogram
in 030 mode the EEPROM of the module with the 'Save' button.



index=118