
Bus Operation
MCF5253 Reference Manual, Rev. 1
Freescale Semiconductor
8-7
Figure 8-3. Read Cycle Flowchart
Figure 8-4. Basic Read Bus Cycle
A basic read bus cycle has six states (S0–S5). The signal timing relationship in the constituent states of a
basic read cycle is as follows:
Table 8-6. Read Cycle States
State
Name
Description
1,2
STATE 0
The read cycle is initiated in state 0 (S0). On the rising edge of BCLK, the MCF5253 places a valid address on
the address bus and drives RW high, if it is not already high.
STATE 1
The appropriate CS and OE are asserted on the falling edge of BCLK.
STATE 2
External Memory/Device
1. Set RW to read
2. Place address on A[23:1]
1. Decode address and select appropriate device
2. Drive data on D[31:16]
3. CS unit asserts TA (internal termination)
or assert TA externally for 1 BCLK cycle (external
termination).
1. Sample TA low and latch data
1. Stop Driving D[31:16]
1. Start next cycle
MCF5253
BCLK
A[23:1]
RW
D[31:16]
TA
S0
S1
S2
S3
S4
S5
CSx
OE
Read
Содержание MCF5253
Страница 1: ...Document Number MCF5253RM Rev 1 08 2008 MCF5253 Reference Manual...
Страница 26: ...MCF5253 Reference Manual Rev 1 xxvi Freescale Semiconductor...
Страница 32: ...MCF5253 Reference Manual Rev 1 xxxii Freescale Semiconductor...
Страница 46: ...MCF5253 Introduction MCF5253 Reference Manual Rev 1 1 14 Freescale Semiconductor...
Страница 62: ...Signal Description MCF5253 Reference Manual Rev 1 2 16 Freescale Semiconductor...
Страница 98: ...Instruction Cache MCF5253 Reference Manual Rev 1 5 10 Freescale Semiconductor...
Страница 104: ...Static RAM SRAM MCF5253 Reference Manual Rev 1 6 6 Freescale Semiconductor...
Страница 128: ...Synchronous DRAM Controller Module MCF5253 Reference Manual Rev 1 7 24 Freescale Semiconductor...
Страница 144: ...Bus Operation MCF5253 Reference Manual Rev 1 8 16 Freescale Semiconductor...
Страница 176: ...System Integration Module SIM MCF5253 Reference Manual Rev 1 9 32 Freescale Semiconductor...
Страница 198: ...Analog to Digital Converter ADC MCF5253 Reference Manual Rev 1 12 6 Freescale Semiconductor...
Страница 246: ...DMA Controller MCF5253 Reference Manual Rev 1 14 18 Freescale Semiconductor...
Страница 282: ...UART Modules MCF5253 Reference Manual Rev 1 15 36 Freescale Semiconductor...
Страница 298: ...Queued Serial Peripheral Interface QSPI Module MCF5253 Reference Manual Rev 1 16 16 Freescale Semiconductor...
Страница 344: ...Audio Interface Module AIM MCF5253 Reference Manual Rev 1 17 46 Freescale Semiconductor...
Страница 362: ...I2 C Modules MCF5253 Reference Manual Rev 1 18 18 Freescale Semiconductor...
Страница 370: ...Boot ROM MCF5253 Reference Manual Rev 1 19 8 Freescale Semiconductor...