M50LPW040K データシートの表示（PDF） - STMicroelectronics
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M50LPW040K Datasheet PDF : 36 Pages
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M50LPW040
Table 6. LPC Bus Read Field Definitions
Clock Clock
Cycle Cycle
Number Count
Field
LAD0- Memory
LAD3
I/O
Description
On the rising edge of CLK with LFRAME Low, the contents
1
1
START
0000b
I
of LAD0-LAD3 must be 0000b to indicate the start of a LPC
cycle.
2
1
CYCTYPE
+ DIR
0100b
I
Indicates the type of cycle. Bits 3:2 must be 01b. Bit 1
indicates the direction of transfer: 0b for read. Bit 0 is 0
3-10
8
ADDR
XXXX
A 32-bit address phase is transferred starting with the most
I
significant nibble first. A23-A31 must be set to 1. A22 = 1 for
Array, A22 = 0 for registers access. For A19-A21 values,
refer to Table 2.
11
1
TAR
1111b
I
The host drives LAD0-LAD3 to 1111b to indicate a
turnaround cycle.
12
1
TAR
1111b
(float)
O
The LPC Flash Memory takes control of LAD0-LAD3 during
this cycle.
13-14
2
WSYNC 0101b
The LPC Flash Memory drives LAD0-LAD3 to 0101b (short
O wait-sync) for two clock cycles, indicating that the data is not
yet available. Two wait-states are always included.
The LPC Flash Memory drives LAD0-LAD3 to 0000b,
15
1
RSYNC 0000b
O indicating that data will be available during the next clock
cycle.
16-17
2
DATA
XXXX
O
Data transfer is two CLK cycles, starting with the least
significant nibble.
18
1
TAR
1111b
O
The LPC Flash Memory drives LAD0-LAD3 to 1111b to
indicate a turnaround cycle.
19
1
TAR
1111b
(float)
N/A
The LPC Flash Memory floats its outputs, the host takes
control of LAD0-LAD3.
Figure 5. LPC Bus Read Waveforms
CLK
LFRAME
LAD0-LAD3
Number of
clock cycles
8/36
START
1
CYCTYPE
+ DIR
1
ADDR
8
TAR
2
SYNC
3
DATA
2
TAR
2
AI04429
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