
FlexBus
17-4
Freescale Semiconductor
If auto-acknowledge is disabled (CSCR
n
[AA] = 0), the external device drives FB_TA to terminate the bus
transfer; if auto-acknowledge is enabled (CSCR
n
[AA] = 1), FB_TA is generated internally after a
specified number of wait states, or the external device may assert external FB_TA before the wait-state
countdown, terminating the cycle early. The device negates FB_CS
n
one cycle after the last FB_TA
asserts. During read cycles, the peripheral must continue to drive data until FB_TA is recognized. For write
cycles, the processor continues driving data one clock after FB_CS
n
is negated.
The number of wait states is determined by CSCR
n
or the external FB_TA input. If the external FB_TA is
used, the peripheral has total control on the number of wait states.
NOTE
External devices should only assert FB_TA while the FB_CS
n
signal to the
external device is asserted.
Because this device shares the FlexBus signals with the SDRAM controller,
this signal tristates between bus cycles.
17.3
Memory Map/Register Definition
The following tables describe the registers and bit meanings for configuring chip-select operation.
shows the chip-select register memory map.
The actual number of chip select registers available depends upon the device and its pin configuration. See
for more details. If the device does not support certain chip select signals or the pin is not
configured for a chip-select function, then that corresponding set of chip-select registers has no effect on
an external pin.
17.3.1
Chip-Select Address Registers (CSAR0 – CSAR5)
The CSAR
n
registers specify the chip-select base addresses.
NOTE
Because the FlexBus module is one of the slaves connected to the crossbar
switch, it is only accessible within a certain memory range. The only
applicable address ranges for which the chip-selects can be active are
0x0000_0000 – 0x3FFF_FFFF and 0xC000_0000 – 0xDFFF_FFFF. Set the
CSAR
n
registers appropriately.
Table 17-2. FlexBus Chip Select Memory Map
Address
Register
Width
(bits)
Access
Reset Value
Section/
Page
0xFC00_8000
+ (n
×
0xC)
Chip-Select Address Register (CSARn)
n = 0 – 5
32
R/W
0x0000_0000
0xFC00_8004
+ (n
×
0xC)
Chip-Select Mask Register (CSMRn)
n = 0 – 5
32
R/W
0x0000_0000
0xFC00_8008
+ (n
×
0xC)
Chip-Select Control Register (CSCRn)
n = 0 – 5
32
R/W
See Section
MCF5329 Reference Manual, Rev 3
Summary of Contents for MCF5329
Page 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...