5.2.3.2
eeShort command
This command initiates a data access in short (24-bit) addressing mode. The
address ADD[27:0] that is accessed with eeShort is calculated as follows:
ADD[27:0] = 0x0FF FFFF & ( (SHADDOFF[11:0] << 12) or LADD[11:0] )
Byte
2nd byte
1st byte
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Content
LADD[11:4]
LADD[3:0]
L[1:0]
RW
0
Parameters
•
bit1 = RW: defines the direction of the data transfer:
-
RW = 0: write mode, LBDIN[7:0] from Host CPU (HLBWR active)
-
RW = 1: read mode, LBDIN[7:0] to Host CPU (HLBRD active)
•
bit[3:2] = L[1:0]: defines the data length, i.e. the number of data bytes
to transfer:
-
L[1:0] = 00
B
: 1 data byte (8-bit data)
-
L[1:0] = 01
B
: 2 data bytes (16-bit data)
-
L[1:0] = 10
B
: 4 data bytes (32-bit data)
-
L[1:0] = 11
B
: setting prohibited
•
bit[15:4] = LADD[11:0]: lower 12 bit of the address
eeShort byte1
eeShort byte2
command
transfer
word
data transfer
L[1:0] = 00
B
L[1:0] = 01
B
L[1:0] = 10
B
data byte1
data byte2
data byte3
data byte4
eeShort byte1
eeShort byte2
command
transfer
halfword
data transfer
data byte1
data byte2
byte
data transfer
data byte
time
time
time
eeShort byte1
eeShort byte2
command
transfer
Figure 5-4 eeShort command flow
Host CPU Interface
Chapter 5
Preliminary User's Manual S19203EE1V3UM00
127
Содержание uPD72257
Страница 39: ...Pin Functions Chapter 2 Preliminary User s Manual S19203EE1V3UM00 39...
Страница 44: ...Chapter 2 Pin Functions 44 Preliminary User s Manual S19203EE1V3UM00...
Страница 46: ...Chapter 2 Pin Functions 46 Preliminary User s Manual S19203EE1V3UM00...
Страница 49: ...Pin Functions Chapter 2 Preliminary User s Manual S19203EE1V3UM00 49...
Страница 52: ...Chapter 2 Pin Functions 52 Preliminary User s Manual S19203EE1V3UM00...
Страница 54: ...Chapter 2 Pin Functions 54 Preliminary User s Manual S19203EE1V3UM00...
Страница 331: ...External Memory Interface Controller Chapter 9 Preliminary User s Manual S19203EE1V3UM00 331...
Страница 343: ......