Fujitsu FR81S User Manual
CHAPTER 50: RAM DIAGNOSIS FUNCTION
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : RAM DIAGNOSIS FUNCTION
FUJITSU SEMICONDUCTOR CONFIDENTIAL
44
5.5. Number of Required Cycles
This section explains the number of required cycles.
The following shows the estimation of the cycle count required for various RAM diagnosis for XBS RAM
and initialization types.
XBS RAM : 48kByte = 12k word address (MB91F522, MB91F523)
64kByte = 16k word address (MB91F524)
96kByte = 24k word address (MB91F525)
128kByte = 32k word address (MB91F526)
Backup RAM : 8kByte = 2k word address
Backup RAM can be estimated in the same way.
(1) "RAM diagnosis (unique)"
⋅
Write (1 cycle)
⋅
Read 1 (1 cycle)
⋅
Read 2 (1 cycle)
Processes above have full word address per a word address and the entire number of cycles is as follows:
(
1
+
1
+
1
)
×
12288(12k)
+1
=
36865
(
1
+
1
+
1
)
×
16384(16k)
+1
=
49153
(
1
+
1
+
1
)
×
24576(24k)
+1
=
73729
(
1
+
1
+
1
)
×
32768(32k)
+1
=
98305
Write Read 1 Read 2
Word
Total
(2) "RAM diagnosis (checker)"
⋅
Write 1 (1 cycle) : W1
⋅
Read 1 (1 cycle) : R1
Processes above have full word address per a word address. To perform the partial write function diagnosis,
five write processes and four read processes are provided for each word address. So, the following is
obtained.
⋅
Write 2 (1 × 5 cycles) : W2
⋅
Read 2 (2 × 4 cycles) : R2
Moreover, the same processing is repeated with data different from above data. The entire number of cycles
is as follows:
( (
1
+
1
)
×
12288(12k)
+1 + 5
+ 8
)
×
2
= 49180
( (
1
+
1
)
×
16384(16k)
+1 + 5
+ 8
)
×
2
= 65564
( (
1
+
1
)
×
24576(24k)
+1 + 5
+ 8
)
×
2
= 98332
( (
1
+
1
)
×
32768(32k)
+1 + 5
+ 8
)
×
2
= 131100
W1
R1
Word
W2 R2
Repetition
Total
MB91520 Series
MN705-00010-1v0-E
2165