External Bus Interface (EBI)
Freescale Semiconductor
30-51
PXR40 Microcontroller Reference Manual, Rev. 1
50/15.2 = 3 with 4.4ns remaining (so we need at least 3 wait states, now check setup time)
15.2-4.4=10.8ns (this is the achieved input data setup time)
Since actual input setup (10.8ns) is greater than the input setup spec (4.0ns), 3 wait states is sufficient. If
the actual input setup was less than 4.0ns, we would have to use 4 wait states instead.
30.5.3.2
Timing and Connections for Asynchronous Memories
The connections to an asynchronous memory are the same as for a synchronous memory, except that the
D_CLKOUT, D_TS, and D_BDIP signals are not used.
shows a block diagram of an MCU
connected to an asynchronous memory.
Figure 30-39. MCU Connected to Asynchronous Memory
shows a timing diagram of a read operation to a 16-bit asynchronous memory using 3 wait
states.
shows a timing diagram of a write operation to a 16-bit asynchronous memory using 3 wait
states.
Flash memories typically use one WE signal as shown, RAMs use 2 or 4 (16-bit or 32-bit).
*
CS0
D_ADD[9:30]
D_OE
MCU
CE
WE*
A[0:21]
D[0:15]
OE
Asynchronous
Memory
D_WE0
D_ADD_DAT[0:15]
Summary of Contents for PXR4030
Page 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Page 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Page 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Page 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Page 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Page 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Page 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...