Circuit Board Reference Manual

Memory Map/Register Definitions
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 24-21
24.3.4.3 External Request Address Mask Register (EREQMASK)
This register contains an address mask value used for the compare that determines a hit for the external
acknowledge signal. A 0 indicates a compare and a 1 is a do not care. This address mask value can be valid
for comm bus cycles, system SRAM, external memory, or comm bus peripherals. This register can be read
or written at any time. The reset state of this register is set to all zeros.
24.3.4.4 External Request Control Register (EREQCTRL)
This register contains the control information for the external request (DREQ) and external acknowledge
(DACK) signals. This register can be read or written at any time. The reset state of this register is set to all
zeros.
313029282726252423222120191817161514131211109876543210
R
W
Base Address
Reset00000000000000000000000000000000
Reg
Addr
MBAR + 0x0D00 (EREQBAR0); 0x0D10 (EREQBAR1)
Figure 24-20. External Request Base Address Register
313029282726252423222120191817161514131211109876543210
R
W
Address Mask
Reset00000000000000000000000000000000
Reg
Addr
MBAR + 0x0D04 (EREQMASK0); 0x0D14 (EREQMASK1)
Figure 24-21. External Request Address Mask Register (EREQMASK)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R0000000000000000
W
Reset0000000000000000
1514131211109876543210
R00000000 MD BSEL DACKWID SYNC EN
W
Reset0000000000000000
Reg
Addr
MBAR + 0x0D08 (EREQCTRL0); 0x0D18 (EREQCTRL1)
Figure 24-22. External Request Control Register (EREQCTRL)