XC2200 Derivatives
System Units (Vol. 1 of 2)
The External Bus Controller EBC
User’s Manual
9-2
V2.1, 2008-08
EBC_X8, V1.0d1
The five register sets (FCONCSx/TCONCSx/ADDRSELx, x = 7, 4, 3, 2, 1) define five
independent “address windows”, whereas all external accesses outside these windows
are controlled via registers FCONCS0 and TCONCS0. Chip Select signals CS0 … CS4
and their associated programmable address windows belong to access to resources on
the external bus. Chip Select signal CS7 and its associated fixed address window is
used for access to the internal MultiCAN and USIC modules on the LXBus.
The external bus timing is related to the reference CLocK OUTput (CLKOUT
1)
). All bus
signals are generated in relation to the rising edge of this clock. The external bus protocol
is compatible with those of the C166 Family and the XC166 Family.
These improvements are configured via an enhanced register set (see above) in
comparison to C166 Family. The C16x registers SYSCON and BUSCONx are no longer
used. But because the configuration of the external bus controller is done during the
application initialization, only some initialization code has to be adapted for using the
new EBC module instead of the C16x external bus controller.
1) The term CLKOUT refers to the reference clock output signal which is generated by selecting
f
SYS
as source
signal for the clock output signal EXTCLK on pin P2.8 and by enabling the high-speed clock driver on this pin.
