mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 416

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

Memory Controller
15.5.4.2.7 Address Multiplexing. You can control the address signals that go to the
external bus. The AMA and AMB fields of the MxMR control how the address signals are
multiplexed. The SAM bit in the option register determines the address multiplexing for the
first clock cycle. The AMX field in the RAM word determines the multiplexing for subsequent
clock cycles. The lower address pins can be multiplexed between the internal upper or lower
address signals. The SAM bit outputs the upper address signals and the AMX field outputs
the lower address signals. Using the AMX field, you can output the contents of the memory
address register (MAR) on the address pins. See Table 15-6 for general configuration.
Table 15-7 shows how the AMA and AMB fields can be defined to interface with a wide
range of DRAM modules. Figure 15-31 illustrates address multiplex timing.
CLKOUT/GCLK2
GCLK1
A[0:31]
TS
SIGNALS
AMA/AMB
000
001
010
011
100
101
RES
RES
RES
RES
A16
A6
A4
RES
A17
Freescale Semiconductor, Inc.
A8
A7
A6
A5
A4
Figure 15-31. Address Multiplex Timing
For More Information On This Product,
ADDRESS CONTROLLED
Table 15-7. Address Multiplexing
A18
A10
A9
A8
A7
A6
A5
UPPER ADDRESS
MPC823 REFERENCE MANUAL
BY SAM
A19
A11
A10
A9
A8
A7
A6
Go to: www.freescale.com
A20
A12
A11
A10
RAM WORD 1
A9
A8
A7
A21
A13
A12
A11
A10
A9
A8
A22
A14
A13
A12
A11
A10
A9
A23
A15
A14
A13
A12
A11
A10
PINS
A24
A16
A15
A14
A13
A12
LOWER ADDRESS
ADDRESS CONTROLLED
A25
A17
A16
A15
A14
A13
BY AMX
A26
A18
A17
A16
A15
A14
RAM WORD 2
A27
A19
A18
A17
A16
A15
A14
A28
A20
A19
A18
A17
A16
A15
A29
A21
A20
A19
A18
A17
A16
MOTOROLA
A30
A22
A21
A20
A19
A18
A17
A31
A23
A22
A21
A20
A19
A18