Datasheet

SAM9G20
DS60001516A-page 138  2017 Microchip Technology Inc.
19.6.6.4 Multiplexing of CompactFlash Signals on EBI Pins
Table 19-8 and Table 19-9 illustrate the multiplexing of the CompactFlash logic signals with other EBI signals on the EBI pins. The EBI
pins in Table 19-8 are strictly dedicated to the CompactFlash interface as soon as the EBI_CS4A and/or EBI_CS5A bit(s) in the EBI_CSA
register is/are set. These pins must not be used to drive any other memory devices.
The EBI pins in Tab le 19-9 remain shared between all memory areas when the corresponding CompactFlash interface is enabled
(EBI_CS4A = 1 and/or EBI_CS5A = 1).
19.6.6.5 Application Example
Figure 19-5 illustrates an example of a CompactFlash application. CFCS0 and CFRNW signals are not directly connected to the Com-
pactFlash slot 0, but do control the direction and the output enable of the buffers between the EBI and the CompactFlash Device. The
timing of the CFCS0 signal is identical to the NCS4 signal. Moreover, the CFRNW signal remains valid throughout the transfer, as does
the address bus. The CompactFlash _WAIT signal is connected to the NWAIT input of the Static Memory Controller. For details on these
waveforms and timings, refer to Section 20. “Static Memory Controller (SMC)”.
Table 19-8: Dedicated CompactFlash Interface Multiplexing
Pins
CompactFlash Signals EBI Signals
CS4A = 1 CS5A = 1 CS4A = 0 CS5A = 0
NCS4/CFCS0 CFCS0 NCS4
NCS5/CFCS1 CFCS1 NCS5
Table 19-9: Shared CompactFlash Interface Multiplexing
Pins
Access to CompactFlash Device Access to Other EBI Devices
CompactFlash Signals EBI Signals
NRD/CFOE CFOE NRD
NWR0/NWE/CFWE CFWE NWR0/NWE
NWR1/NBS1/CFIOR CFIOR NWR1/NBS1
NWR3/NBS3/CFIOW CFIOW NWR3/NBS3
A25/CFRNW CFRNW A25