TC1796
System Units (Vol. 1 of 2)
LMB External Bus Unit
User’s Manual 13-26 V2.0, 2007-07
EBU, V2.0
13.5.1 External Memory Regions
The EBU of the TC1796 supports four (plus one for emulation purposes) memory
regions, which have its own associated chip select outputs CS[3:0] (and CSEMU). Each
of these regions has a set of control registers to specify the type of memory/peripheral
device and the access parameters.
Each of the four user-programmable regions (x = 0-3 is the numbering index of these
regions) is configurable through registers EBU_ADDRSELx, EBU_BUSCONx, and
EBU_BUSAPx. The access parameters for each of the regions can be programmed
individually to accommodate different types of external devices.
The emulator region is programmable in the same way as the user-programmable
regions through registers EBU_EMUAS, EBU_EMUBC, and EBU_EMUBAP. Each of
the regions can be defined for either asynchronous demultiplexed or synchronous Burst
Flash access.
Table 13-11 lists the programmable parameters that are available for the five external
regions (region 0 to 3 and the emulator memory region).
Table 13-10 EBU Address Regions, Registers and Chip Selects
Region Associated
Chip Select
Address Select
Registers
Bus
Configuration
Registers
Bus Access
Parameters
Registers
Region 0 CS0 EBU_ADDRSEL0 EBU_BUSCON0 EBU_BUSAP0
Region 1 CS1 EBU_ADDRSEL1 EBU_BUSCON1 EBU_BUSAP1
Region 2 CS2 EBU_ADDRSEL2 EBU_BUSCON2 EBU_BUSAP2
Region 3 CS3 EBU_ADDRSEL3 EBU_BUSCON3 EBU_BUSAP3
Emulator
region
CSEMU EBU_EMUAS EBU_EMUBC EBU_EMUBAP
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