![Infineon Technologies TC1796 Скачать руководство пользователя страница 836](http://html1.mh-extra.com/html/infineon-technologies/tc1796/tc1796_user-manual_2055437836.webp)
TC1796
System Units (Vol. 1 of 2)
LMB External Bus Unit
User’s Manual
13-58
V2.0, 2007-07
EBU, V2.0
Note: Due to the two-cycle delay in Asynchronous Mode between the sampling of the
WAIT input and its evaluation by the EBU, the Command Phase must always be
programmed to be at least two LMBCLK cycles (via EBU_BUSAPx.WAITRDC or
EBU_EMUBAP.WAITWRC) in this mode.
shows an example of the extension of the Command Phase through the
WAIT input in synchronous mode:
•
At LMBCLK edge 1 (at the end of the Address Phase), the EBU samples the WAIT
input as low and starts the first cycle of the Command Phase (CPi1 - internally
programmed).
•
At LMBCLK edge 2, the EBU samples the WAIT input as low and starts an additional
Command Phase cycle (CPe2 - externally generated) as a result of the WAIT input
sampled as low at LMBCLK edge 1.
•
At LMBCLK edge 3, the EBU samples the WAIT input as high and starts an additional
Command Phase cycle (CPe3 - externally generated) as a result of the WAIT input
sampled as low at LMBCLK edge 2.
•
Finally at LMBCLK edge 4, as a result of the WAIT input sampled as high at point 3,
the EBU terminates the Command Phase, reads the input data from D[31:0] and
starts the Recovery Phase.
Note: Synchronous operation means that even though access to the device may be
asynchronous, the control logic generating the control signals must meet setup
and hold time requirements with respect to LMBCLK.