TC1796
System Units (Vol. 1 of 2)
Clock System and Control
User’s Manual
3-34
V2.0, 2007-07
Clock, V2.0
Suspend Mode Control
The operation of the fractional divider can be controlled by the Debug Suspend Request
input. This input is activated in suspend mode by the on-chip debug control logic. In
suspend mode, module registers are accessible for read and write actions, but other
module internal functions are frozen. Suspend mode is entered one
f
IN
clock cycle after
the Debug Suspend Request has been acknowledged by the Debug Suspend
Acknowledge signal (granted suspend mode)
and
FDR.SC is not equal 00
B
(clock output
signal disabled). Suspend mode is immediately entered when bit SM is set to 1
and
FDR.SC is not equal 00
B
(immediate suspend mode).
The state of the Debug Suspend Request and Debug Suspend Acknowledge signal is
latched in two status flags of register FDR, SUSREQ and SUSACK. Debug Suspend
Request and (Debug Suspend Acknowledge or bit SM) must remain set both to maintain
the suspend mode.
Figure 3-9
Suspend Mode Configuration
The Kernel Disable Request signal becomes always active when the Module Disable
Request signal is activated, independently of the suspend mode settings in the fractional
divider logic.
External Clock Enable
When the module clock generation has been disabled by software (setting
FDR.DISCLK = 1), the disable state can be exited (hardware controlled) when the
External Clock Enable input = 1. This feature is enabled when FDR.ENHW = 1.
MCA05607
SUS
REQ
SUS
ACK
&
Register FDR
Fractional Divider
SC
SC not
equal 00
B
&
switch
f
OUT
off
SM
Debug Suspend
Request
Debug Suspend
Acknowledge
Module Disable
Request
Kernel Disable
Request
≥
1
≥
1