Cirrus Logic EP93xx - Manual (Page 50)

2-12 DS785UM1
Copyright 2007 Cirrus Logic
ARM920T Core and Advanced High-Speed Bus (AHB)
EP93xx User’s Guide
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2.3.2 AHB-to-APB Bridge
The AHB-to-APB Bridge is an AHB slave that provides an interface between the high-speed
AHB and the low-power APB. Read and write transfers on the AHB are converted into
equivalent transfers on the APB. As the APB is not pipelined. Wait states are added during
transfers to and from the APB when the AHB is required to wait for the APB.
The main sections of this bridge are:
• AHB slave bus interface
• APB transfer state machine, which is independent of the device memory map
• APB output signal generation.
2.3.2.1 Function and Operation of the AHB-to-APB Bridge
The AHB-to-APB Bridge responds to access requests from the currently granted AHB
master. The AHB accesses are then converted into APB accesses.
If an undefined location is accessed, operation of the system continues as normal, but no
peripherals are selected. The APB bridge acts as the only master on the APB.
The APB memory map is shown in Table 2-3 .
Table 2-3. APB Peripheral Address Range
Address Range
Register
Width
Peripheral
Type
Peripheral
0x8095_0000 - 0x9000_FFFF - - Reserved
0x8094_0000 - 0x8094_FFFF 16 APB Watchdog Timer
0x8093_0000 - 0x8093_FFFF 32 APB Syscon
0x8092_0000 - 0x8092_FFFF 32 APB Real time clock
0x8091_0000 - 0x8091_FFFF 16 APB Pulse Width Modulation
0x8090_0000 - 0x8090_FFFF 32 APB Touchscreen
0x808F_0000 - 0x808F_FFFF 16 APB Key Matrix
0x808E_0000 - 0x808E_FFFF 32 APB UART3
0x808D_0000 - 0x808D_FFFF 8 APB UART2
0x808C_0000 - 0x808C_FFFF 32 APB UART1
0x808B_0000 - 0x808B_FFFF 32 APB IrDA
0x808A_0000 - 0x808A_FFFF 16 APB SPI
0x8089_0000 - 0x8089_FFFF - - Reserved
0x8088_0000 - 0x8088_FFFF 32 APB AAC
0x8087_0000 - 0x8087_FFFF - - Reserved
0x8086_0000 - 0x8086_FFFF - - Reserved
0x8085_0000 - 0x8085_FFFF - - Reserved
0x8084_0000 - 0x8084_FFFF 16 APB GPIO
0x8083_0000 - 0x8083_FFFF 32 APB Security
0x8082_0000 - 0x8082_FFFF 32 APB I2S
0x8081_0000 - 0x8081_FFFF 32 APB Timers
0x8080_0000 - 0x8080_FFFF - - Reserved
0x8010_0000 - 0x807F_FFFF - - Reserved