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136 Hardware Reference Manual
Intel
®
IXP2800 Network Processor
Intel XScale
®
Core
3.12.1.3 Address Spaces for XPI Internal Devices
Table 53 shows the address space assignment for XPI devices.
Table 52. Data Transaction Alignment
Interface Units APB Bus Read Write
GRegs 32 bits 32 bits 32 bits
UART 32 bits 32 bits 32 bits
GPIO 32 bits 32 bits 32 bits
Timer 32 bits 32 bits 32 bits
Slowport
Microprocessor Access
8 bits 8 bits 8 bits
16 bits 16 bits 16 bits
32 bits 32 bits 32 bits
Slowport
Flash Memory Access
1
1. The flash memory interface only supports 8-bit wide flash devices. APB write transactions are assumed to be 8-bits wide,
and correspond to one write cycle at the flash interface. APB read transactions are assumed to be 32-bits wide, and corre-
spond to four flash read cycles for the 32-bit read mode set in the SP_FRM register. However, for the flash register read
mode (8-bit read mode), it only needs one flash read cycle of 8-bit data and passes it back to APB directly. By default, the
32-bit read mode is set. It is advisable to stay in this mode most of the time and not change them dynamically during ac-
cesses.
32 bits for 32-bit read mode, 8
bits for register read mode;
8 bits for write;
Assemble 8 bits into 32-bit data for
32-bit read mode; 8 bits for register
read mode (8-bit read mode).
8 bits
CSR Access 32 bits 32 bits 32 bits
Table 53. Address Spaces for XPI Internal Devices
Units Starting Address Ending Address
GPIO 0xC0010000 0xC0010040
TIMER 0xC0020000 0xC0020040
UART 0xC0030000 0xC003001C
PMU 0xC0050000 0xC0050E00
Slowport CSR 0xC0080000 0xC0080028
Slowport Device 0xC4000000 0xC7FFFFFF